In Module 1, Topic G, students review material covered throughout the module. Additionally, students discuss the structure of geometry as an axiomatic system.

Content Standard(s):

Mathematics MA2015 (2016) Grade: 9-12 Geometry

4 ) Develop definitions of rotations, reflections, and translations in terms of angles, circles, perpendicular lines, parallel lines, and line segments. [G-CO4]

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.HS.4- Given a geometric figure of a reflection or a translation of that figure, identify if the geometric figure is a reflection or translation.

Mathematics MA2015 (2016) Grade: 9-12 Geometry

8 ) Explain how the criteria for triangle congruence, angle-side-angle (ASA), side-angle-side (SAS), and side-side-side (SSS), follow from the definition of congruence in terms of rigid motions. [G-CO8]

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.HS.8- Given two congruent triangles and angle measures of one of the triangles, identify the angle measures of the other triangle.

Mathematics MA2015 (2016) Grade: 9-12 Geometry

10 ) Prove theorems about triangles. Theorems include measures of interior angles of a triangle sum to 180^{o}, base angles of isosceles triangles are congruent, the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length, and the medians of a triangle meet at a point. [G-CO10]

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.HS.10- Given a measure of a leg or base angle of an isosceles triangle, identify the measure of the other leg or other base angle.

Mathematics MA2015 (2016) Grade: 9-12 Geometry

11 ) Prove theorems about parallelograms. Theorems include opposite sides are congruent, opposite angles are congruent; the diagonals of a parallelogram bisect each other; and conversely, rectangles are parallelograms with congruent diagonals. [G-CO11]

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.HS.11- Given the measure of one side or one angle of a parallelogram, identify the measure of the opposite side or opposite angle.

Mathematics MA2015 (2016) Grade: 9-12 Geometry

12 ) Make formal geometric constructions with a variety of tools and methods such as compass and straightedge, string, reflective devices, paper folding, and dynamic geometric software. Constructions include copying a segment; copying an angle; bisecting a segment; bisecting an angle; constructing perpendicular lines, including the perpendicular bisector of a line segment; and constructing a line parallel to a given line through a point not on the line. [G-CO12]

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.HS.12- Given a drawing with angles and a protractor overlay, determine which angles are congruent. Sample image below.
Image

Mathematics MA2015 (2016) Grade: 9-12 Geometry

13 ) Construct an equilateral triangle, a square, and a regular hexagon inscribed in a circle. [G-CO13]

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.HS.13- Identify an equilateral triangle from a set of triangles or identify a regular hexagon from a set of hexagons. Make sure sides/angles are marked so that students can identify congruence.

Mathematics MA2019 (2019) Grade: 9-12 Geometry with Data Analysis

21. Represent transformations and compositions of transformations in the plane (coordinate and otherwise) using tools such as tracing paper and geometry software.

a. Describe transformations and compositions of transformations as functions that take points in the plane as inputs and give other points as outputs, using informal and formal notation.

b. Compare transformations which preserve distance and angle measure to those that do not.

Unpacked Content

Evidence Of Student Attainment:

Students:
Given a variety of transformations (translations, rotations, reflections, and dilations),

Represent the transformations and compositions of transformations in the plane using a variety of methods (e.g., technology, transparencies, semi-transparent mirrors (MIRAs), patty paper, compass).

Describe transformations and compositions of transformations functions that take points in the plane as inputs and give other points as outputs, explain why this satisfies the definition of a function, and adapt function notation to that of a mapping [e.g., f(x,y) → f(x+a, y+b)].

Compare transformations that preserve distance and angle to those that do not.

Teacher Vocabulary:

Transformation

Reflection

Translation

Rotation

Dilation

Isometry

Composition

Horizontal stretch

Vertical stretch

Horizontal shrink

Vertical shrink

Clockwise

Counterclockwise

Symmetry

Preimage

Image

Knowledge:

Students know:

Characteristics of transformations (translations, rotations, reflections, and dilations).

Methods for representing transformations.

Characteristics of functions.

Conventions of functions with mapping notation.

Skills:

Students are able to:

Accurately perform dilations, rotations, reflections, and translations on objects in the coordinate plane with and without technology.

Communicate the results of performing transformations on objects and their corresponding coordinates in the coordinate plane, including when the transformation preserves distance and angle.

Use the language and notation of functions as mappings to describe transformations.

Understanding:

Students understand that:

Mapping one point to another through a series of transformations can be recorded as a function.

Some transformations (translations, rotations, and reflections) preserve distance and angle measure, and the image is then congruent to the pre-image, while dilations preserve angle but not distance, and the pre-image is similar to the image.

Distortions, such as only a horizontal stretch, preserve neither.

Diverse Learning Needs:

Essential Skills:

Learning Objectives: GEO.21.1: Define distance, angle, input, output, plane, translation, reflection, rotation, and dilation.
GEO.21.2: Compare transformation that preserve distance and angle to those that do not (e.g., translation versus horizontal stretch).
GEO.21.3: Describe transformations as functions that take points in a plane as inputs and give other points as outputs.
GEO.21.4: Represent transformation in the plane.
GEO.21.5: Generate an input output table.
GEO.21.6: Compare the distance and angles of the figures from the pre-image to the image.
GEO.21.7: Measure distance and angle(s) of an image.

Prior Knowledge Skills:

Define rotation, reflection, and translation.

Recognize translations (slides), rotations (turns), and reflections (flips).

Distinguish between lines and line segments.

Demonstrate how to measure length.

Demonstrate how to use a protractor to measure angles.

Define square root, expressions, and approximations.

Identify perfect squares and square roots.

Demonstrate how to locate points on a vertical or horizontal number line.

Define ordered pairs.

Show how to plot points on a Cartesian plane.

Locate the origin on the coordinate plane.

Identify the length between vertices on a coordinate plane.

Recall how to read a graph or table.

Draw and label a coordinate plane.

Plot independent (input) and dependent (output) values on a coordinate plane.

Plot pairs of integers and/or rational numbers on a coordinate plane.

Arrange integers and/or rational numbers on a horizontal or vertical number line.

Locate the position of integers and/or rational numbers on a horizontal or vertical number line.

Define quadrant, coordinate plane, coordinate axes (x-axis and y-axis), horizontal, vertical, and reflection.

Calculate the distances between points having the same first or second coordinate using absolute value.

Define number line.

Demonstrate the location of positive and negative numbers on a vertical and horizontal number line.

Calculate missing input and/or output values in a table.

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.10.21 Identify and/or model characteristics of a geometric figure that has undergone a transformation (reflection, rotation, translation) by drawing, explaining, or using manipulatives.

Mathematics MA2019 (2019) Grade: 9-12 Geometry with Data Analysis

22. Explore rotations, reflections, and translations using graph paper, tracing paper, and geometry software.

a. Given a geometric figure and a rotation, reflection, or translation, draw the image of the transformed figure using graph paper, tracing paper, or geometry software.

b. Specify a sequence of rotations, reflections, or translations that will carry a given figure onto another.

c. Draw figures with different types of symmetries and describe their attributes.

Unpacked Content

Evidence Of Student Attainment:

Students:
Given a geometric figure,

Explore rotations, reflections, and translations using graph paper, tracing paper, and geometry software.

Produce the image of the figure under a rotation, reflection, or translation using graph paper, tracing paper, or geometry software.

Describe and justify the sequence of transformations that will carry a given figure onto another.

Draw figures such as rectangles, parallelograms, trapezoids, or regular polygons.

Identify which figures that have rotations or reflections that carry the figure onto itself.

Perform and communicate rotations and reflections that map the object to itself.

Distinguish these transformations from those which do not carry the object back to itself.

Describe the relationship of these findings to symmetry.

Teacher Vocabulary:

Transformation

Reflection

Translation

Rotation

Dilation

Isometry

Composition

horizontal stretch

vertical stretch

horizontal shrink

vertical shrink

Clockwise

Counterclockwise

Symmetry

Trapezoid

Square

Rectangle

Regular polygon

parallelogram

Mapping

preimage

Image

Knowledge:

Students know:

Characteristics of transformations (translations, rotations, reflections, and dilations).

Techniques for producing images under transformations using graph paper, tracing paper, or geometry software.

Characteristics of rectangles, parallelograms, trapezoids, and regular polygons.

Skills:

Students are able to:

Accurately perform dilations, rotations, reflections, and translations on objects in the coordinate plane with and without technology.

Communicate the results of performing transformations on objects and their corresponding coordinates in the coordinate plane.

Understanding:

Students understand that:

Mapping one point to another through a series of transformations can be recorded as a function.

Since translations, rotations and reflections preserve distance and angle measure, the image is then congruent.

The same transformation may be produced using a variety of tools, but the geometric sequence of steps that describe the transformation is consistent.

Diverse Learning Needs:

Essential Skills:

Learning Objectives: GEO.22.1: Define rotations, reflections, and translations in terms of angles, circles, perpendicular lines, parallel lines, and line segments.
GEO.22.2: Describe the effects of rotations, reflection, and translations on two dimensional figures using coordinates.
GEO.22.3: Illustrate figures transformed by a rotation, reflection or translation.
GEO.22.4: Describe the process of transforming a given figure.
GEO.22.5: Graph a figure on a coordinate plane.

Prior Knowledge Skills:

Recognize dilations.

Recognize translations.

Recognize rotations.

Recognize reflections.

Define rotation, reflection, and translation.

Recognize translations (slides), rotations (turns), and reflections (flips).

Distinguish between lines and line segments.

Identify parallel lines.

Demonstrate how to locate points on a vertical or horizontal number line.

Define ordered pairs.

Show how to plot points on a Cartesian plane.

Locate the origin on the coordinate plane.

Identify the length between vertices on a coordinate plane.

Recall how to read a graph or table.

Draw and label a coordinate plane.

Plot independent (input) and dependent (output) values on a coordinate plane.

Plot pairs of integers and/or rational numbers on a coordinate plane.

Arrange integers and/or rational numbers on a horizontal or vertical number line.

Locate the position of integers and/or rational numbers on a horizontal or vertical number line.

Define quadrant, coordinate plane, coordinate axes (x-axis and y-axis), horizontal, vertical, and reflection.

Demonstrate when two ordered pairs differ only by signs, the locations of the points are related by reflections across one or both axes.

Calculate the distances between points having the same first or second coordinate using absolute value.

Define number line.

Demonstrate the location of positive and negative numbers on a vertical and horizontal number line.

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.10.21 Identify and/or model characteristics of a geometric figure that has undergone a transformation (reflection, rotation, translation) by drawing, explaining, or using manipulatives.

Mathematics MA2019 (2019) Grade: 9-12 Geometry with Data Analysis

23. Develop definitions of rotation, reflection, and translation in terms of angles, circles, perpendicular lines, parallel lines, and line segments.

Unpacked Content

Evidence Of Student Attainment:

Students:

Use geometric terminology (angles, circles, perpendicular lines, parallel lines, and line segments) to describe the series of steps necessary to produce a rotation, reflection, or translation.

Use these descriptions to communicate precise definitions of rotation, reflection, and translation.

Teacher Vocabulary:

Transformation

Reflection

Translation

Rotation

Dilation

Isometry

Composition

Clockwise

Counterclockwise

Preimage

Image

Knowledge:

Students know:

Characteristics of transformations (translations, rotations, reflections, and dilations).

-Properties of a mathematical definition, i.e., the smallest amount of information and properties that are enough to determine the concept. (Note: may not include all information related to concept).

Skills:

Students are able to:

Accurately perform rotations, reflections, and translations on objects with and without technology.

Communicate the results of performing transformations on objects.

Use known and developed definitions and logical connections to develop new definitions.

Understanding:

Students understand that:

Geometric definitions are developed from a few undefined notions by a logical sequence of connections that lead to a precise definition.

A precise definition should allow for the inclusion of all examples of the concept and require the exclusion of all non-examples.

Diverse Learning Needs:

Essential Skills:

Learning Objectives: GEO.23.1: Define rotations, reflections, and translations in terms of angles, circles, perpendicular lines, parallel lines, and line segments.
GEO.23.2: Describe the effects of rotations, reflection, and translations on two dimensional figures using coordinates.
GEO.23.3: Describe the effects of rotations, reflections, and translations in terms of angles, circles, perpendicular lines, parallel lines, and line segments.
GEO.23.4: Describe the process of transforming a given figure.
GEO.23.5: Illustrate figures transformed by a rotation, reflection or translation.
GEO.23.6: Recognize the type of transformation from a pre-image to an image.

Prior Knowledge Skills:

Recognize dilations.

Recognize translations.

Recognize rotations.

Recognize reflections.

Analyze an image and its dilation to determine if the two figures are similar.

Define dilation.

Recall how to find scale factor.

Give examples of scale drawings.

Recognize translations.

Recognize reflections.

Recognize rotations.

Identify parallel lines.

Compare translations to reflections.

Compare reflections to rotations.

Compare rotations to translations.

Define diameter, radius, circumference, area of a circle, and formula.

Identify and label parts of a circle.

Recognize the attributes of a circle.

Define rotation, reflection, and translation.

Recognize translations (slides), rotations (turns), and reflections (flips).

Define square root, expressions, and approximations.

Demonstrate how to locate points on a vertical or horizontal number line.

Define ordered pairs.

Show how to plot points on a Cartesian plane.

Locate the origin on the coordinate plane.

Identify the length between vertices on a coordinate plane.

Recall how to read a graph or table.

Draw and label a coordinate plane.

Plot independent (input) and dependent (output) values on a coordinate plane.

Plot pairs of integers and/or rational numbers on a coordinate plane.

Arrange integers and/or rational numbers on a horizontal or vertical number line.

Locate the position of integers and/or rational numbers on a horizontal or vertical number line.

Define quadrant, coordinate plane, coordinate axes (x-axis and y-axis), horizontal, vertical, and reflection.

Demonstrate when two ordered pairs differ only by signs, the locations of the points are related by reflections across one or both axes.

Calculate the distances between points having the same first or second coordinate using absolute value.

Define number line.

Demonstrate the location of positive and negative numbers on a vertical and horizontal number line.

Calculate missing input and/or output values in a table.

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.10.21 Identify and/or model characteristics of a geometric figure that has undergone a transformation (reflection, rotation, translation) by drawing, explaining, or using manipulatives.

Mathematics MA2019 (2019) Grade: 9-12 Geometry with Data Analysis

24. Define congruence of two figures in terms of rigid motions (a sequence of translations, rotations, and reflections); show that two figures are congruent by finding a sequence of rigid motions that maps one figure to the other.

Example: △ABC is congruent to △XYZ since a reflection followed by a translation maps △ABC onto △XYZ.

Unpacked Content

Evidence Of Student Attainment:

Students:

Given two geometric figures, determine if a sequence of rotations, reflections, and translations will carry the first to the second, and if so justify their congruence by the definition of congruence in terms of rigid motions.

Teacher Vocabulary:

Rigid motions

Congruence

Knowledge:

Students know:

Characteristics of translations, rotations, and reflections including the definition of congruence.

Techniques for producing images under transformations using graph paper, tracing paper, compass, or geometry software.

Geometric terminology (e.g., angles, circles, perpendicular lines, parallel lines, and line segments) which describes the series of steps necessary to produce a rotation, reflection, or translation.

Skills:

Students are able to:

Use geometric descriptions of rigid motions to accurately perform these transformations on objects.

Communicate the results of performing transformations on objects.

Understanding:

Students understand that:

Any distance preserving transformation is a combination of rotations, reflections, and translations.

If a series of translations, rotations, and reflections can be described that transforms one object exactly to a second object, the objects are congruent.

Diverse Learning Needs:

Essential Skills:

Learning Objectives: GEO.24.1: Define congruence.
GEO.24.2: Applying the definition of congruence determine if two figures are congruent.
GEO.24.3: Illustrate a sequence of rigid motions on a coordinate plane that maps one figure to another.
GEO.24.4: Illustrate a vertical and horizontal shift on a coordinate plane. Example: Rectangle PQRS has vertices P(-3,5), Q(-4,2), R (3,0), 5(4,3). Translate PQRS vertically 3 units.
GEO.24.5: Recognize composition of transformations.
GEO.24.6: Graph a figure on a coordinate plane.

Prior Knowledge Skills:

Recognize dilations.

Recognize translations.

Recognize rotations.

Recognize reflections.

Analyze an image and its dilation to determine if the two figures are similar.

Define dilation.

Recall how to find scale factor.

Give examples of scale drawings.

Recognize translations.

Recognize reflections.

Recognize rotations.

Identify parallel lines.

Define congruent and sequence.

Compare translations to reflections.

Compare reflections to rotations.

Compare rotations to translations.

Identify congruent figures.

Define diameter, radius, circumference, area of a circle, and formula.

Identify and label parts of a circle.

Recognize the attributes of a circle.

Define rotation, reflection, and translation.

Recognize translations (slides), rotations (turns), and reflections (flips).

Define square root, expressions, and approximations.

Demonstrate how to locate points on a vertical or horizontal number line.

Define ordered pairs.

Show how to plot points on a Cartesian plane.

Locate the origin on the coordinate plane.

Identify the length between vertices on a coordinate plane.

Recall how to read a graph or table.

Draw and label a coordinate plane.

Plot independent (input) and dependent (output) values on a coordinate plane.
M. 6.13.2: Plot pairs of integers and/or rational numbers on a coordinate plane.
M. 6.13.3: Arrange integers and/or rational numbers on a horizontal or vertical number line.
M. 6.13.4: Locate the position of integers and/or rational numbers on a horizontal or vertical number line. M. 6.11.1: Define quadrant, coordinate plane, coordinate axes (x-axis and y-axis), horizontal, vertical, and reflection. M. 6.11a.3: Demonstrate when two ordered pairs differ only by signs, the locations of the points are related by reflections across one or both axes.
M. 6.11d.1: Calculate the distances between points having the same first or second coordinate using absolute value.
M. 6.10a.1: Define number line.
M. 6.10a.2: Demonstrate the location of positive and negative numbers on a vertical and horizontal number line. M. 6.3.6: Calculate missing input and/or output values in a table.

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.10.24 When given two congruent triangles that have been transformed (limit to a translation), determine the congruent parts. (Ex: Determine which leg on Triangle A is congruent to which leg on Triangle B.)

Mathematics MA2019 (2019) Grade: 9-12 Geometry with Data Analysis

25. Verify criteria for showing triangles are congruent using a sequence of rigid motions that map one triangle to another.

a. Verify that two triangles are congruent if and only if corresponding pairs of sides and corresponding pairs of angles are congruent.

b. Verify that two triangles are congruent if (but not only if) the following groups of corresponding parts are congruent: angle-side-angle (ASA), side-angle-side (SAS), side-side-side (SSS), and angle-angle-side (AAS).

Example: Given two triangles with two pairs of congruent corresponding sides and a pair of congruent included angles, show that there must be a sequence of rigid motions will map one onto the other.

Unpacked Content

Evidence Of Student Attainment:

Students:

Given a triangle and its image under a sequence of rigid motions (translations, reflections, and translations), verify that corresponding sides and corresponding angles are congruent.

Given two triangles that have the same side lengths and angle measures, find a sequence of rigid motions that will map one onto the other.

Use rigid motions and the basic properties of rigid motions (that they preserve distance and angle), which are assumed without proof to establish that the usual triangle congruence criteria make sense and can then be used to prove other theorems.

Teacher Vocabulary:

Corresponding sides and angles

Rigid motions

If and only if

Triangle congruence

Angle-Side-Angle (ASA)

Side-Angle-Side (SAS)

Side-Side->Side (SSS)

Knowledge:

Students know:

Characteristics of translations, rotations, and reflections including the definition of congruence.

Techniques for producing images under transformations.

Geometric terminology which describes the series of steps necessary to produce a rotation, reflection, or translation.

Basic properties of rigid motions (that they preserve distance and angle).

Methods for presenting logical reasoning using assumed understandings to justify subsequent results.

Skills:

Students are able to:

Use geometric descriptions of rigid motions to accurately perform these transformations on objects.

Communicate the results of performing transformations on objects.

Use logical reasoning to connect geometric ideas to justify other results.

Perform rigid motions of geometric figures.

Determine whether two plane figures are congruent by showing whether they coincide when superimposed by means of a sequence of rigid motions (translation, reflection, or rotation).

Identify two triangles as congruent if the lengths of corresponding sides are equal (SSS criterion), if the lengths of two pairs of corresponding sides and the measures of the corresponding angles between them are equal (SAS criterion), or if two pairs of corresponding angles are congruent and the lengths of the corresponding sides between them are equal (ASA criterion).

Apply the SSS, SAS, and ASA criteria to verify whether or not two triangles are congruent.

Understanding:

Students understand that:

If a series of translations, rotations, and reflections can be described that transforms one object exactly to a second object, the objects are congruent.

It is beneficial to have minimal sets of requirements to justify geometric results (e.g., use ASA, SAS, or SSS instead of all sides and all angles for congruence).

Diverse Learning Needs:

Essential Skills:

Learning Objectives: GEO.25.1: Define congruent, corresponding, triangles, angles, and the concept of if and only if.
GEO.25.2: Compare angles and sides of two triangles to determine congruency.
GEO.25.3: Determine the lengths of sides and the measures of angles in triangles.
GEO.25.4: Identify corresponding parts of triangles.

Prior Knowledge Skills:

Define congruent and sequence.

Identify congruent figures.

Recognize attributes of geometric shapes.

Identify the length between vertices on a coordinate plane.

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.10.24 When given two congruent triangles that have been transformed (limit to a translation), determine the congruent parts. (Ex: Determine which leg on Triangle A is congruent to which leg on Triangle B.)

Mathematics MA2019 (2019) Grade: 9-12 Geometry with Data Analysis

30. Develop and use precise definitions of figures such as angle, circle, perpendicular lines, parallel lines, and line segment, based on the undefined notions of point, line, distance along a line, and distance around a circular arc.

Unpacked Content

Evidence Of Student Attainment:

Students:
Given undefined notions of point, line, distance along a line, and distance around a circular arc,

Develop precise definitions of angle, circle, perpendicular line, parallel line, and line segment.

Identify examples and non-examples of angles, circles, perpendicular lines, parallel lines, and line segments.

Teacher Vocabulary:

Point

Line

Segment

Angle

Perpendicular line

Parallel line

Distance

Arc length

Ray

Vertex

Endpoint

Plane

Collinear

Coplanar

Skew

Knowledge:

Students know:

Undefined notions of point, line, distance along a line, and distance around a circular arc.

Properties of a mathematical definition, i.e., the smallest amount of information and properties that are enough to determine the concept. (Note: may not include all information related to concept).

Skills:

Students are able to:

Use known and developed definitions and logical connections to develop new definitions.

Understanding:

Students understand that:

Geometric definitions are developed from a few undefined notions by a logical sequence of connections that lead to a precise definition,
A precise definition should allow for the inclusion of all examples of the concept, and require the exclusion of all non-examples.

Diverse Learning Needs:

Essential Skills:

Learning Objectives: GEO.30.1: Define angle, circle, perpendicular line, parallel line, line segment, and distance.
GEO.30.2: Describe angle, circle, perpendicular line, parallel line, line segment, and distance.
GEO.30.3: Illustrate a point, line, distance along a line, and distance around a circular arc.
GEO.30.4: Identify angle, circle, perpendicular line, parallel line, line segment, and distance.

Define supplementary, complementary, vertical, and adjacent angles; and parallel, perpendicular, and intersecting lines.

Identify all types of angles.

Identify right angles and straight angles.

Demonstrate how to use a protractor to draw an angle.

Define vertices.

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.10.30 Demonstrate perpendicular lines, parallel lines, line segments, angles, and circles by drawing, modeling, identifying or creating.

Mathematics MA2019 (2019) Grade: 9-12 Geometry with Data Analysis

31. Justify whether conjectures are true or false in order to prove theorems and then apply those theorems in solving problems, communicating proofs in a variety of ways, including flow chart, two-column, and paragraph formats.

a. Investigate, prove, and apply theorems about lines and angles, including but not limited to: vertical angles are congruent; when a transversal crosses parallel lines, alternate interior angles are congruent and corresponding angles are congruent; the points on the perpendicular bisector of a line segment are those equidistant from the segment's endpoints.

b. Investigate, prove, and apply theorems about triangles, including but not limited to: the sum of the measures of the interior angles of a triangle is 180?; the base angles of isosceles triangles are congruent; the segment joining the midpoints of two sides of a triangle is parallel to the third side and half the length; a line parallel to one side of a triangle divides the other two proportionally, and conversely; the Pythagorean Theorem using triangle similarity.

c. Investigate, prove, and apply theorems about parallelograms and other quadrilaterals, including but not limited to both necessary and sufficient conditions for parallelograms and other quadrilaterals, as well as relationships among kinds of quadrilaterals.

Example: Prove that rectangles are parallelograms with congruent diagonals.

Unpacked Content

Evidence Of Student Attainment:

Students:

Make, explain, and justify (or refute) conjectures about geometric relationships with and without technology.

Explain the requirements of a mathematical proof.

Present a complete mathematical proof of geometry theorems including the following: vertical angles are congruent. when a transversal crosses parallel lines, alternate interior angles are congruent and corresponding angles are congruent. points on a perpendicular bisector of a line segment are exactly those equidistant from the segment's endpoints.
Critique proposed proofs made by others.

Present a complete mathematical proof of geometry theorems about triangles, including the following: measures of interior angles of a triangle sum to 180o. base angles of isosceles triangles are congruent. the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length. the medians of a triangle meet at a point.
Critique proposed proofs made by others.

Present a complete mathematical proof of geometry theorems about parallelograms, including the following: opposite sides are congruent, opposite angles are congruent, the diagonals of a parallelogram bisect each other, and conversely, rectangles are parallelograms with congruent diagonals.
Critique proposed proofs made by others.

Teacher Vocabulary:

Same side interior angle

Consecutive interior angle

Vertical angles

Linear pair

Adjacent angles

Complementary angles

Supplementary angles

Perpendicular bisector

Equidistant

Theorem Proof

Prove

Transversal

Alternate interior angles

Corresponding angles

Interior angles of a triangle

Isosceles triangles

Equilateral triangles

Base angles

Median

Exterior angles

Remote interior angles

Centroid

Parallelograms

Diagonals

Bisect

Knowledge:

Students know:

Requirements for a mathematical proof.

Techniques for presenting a proof of geometric theorems.

Skills:

Students are able to:

Communicate logical reasoning in a systematic way to present a mathematical proof of geometric theorems.

Generate a conjecture about geometric relationships that calls for proof.

Understanding:

Students understand that:

Proof is necessary to establish that a conjecture about a relationship in mathematics is always true, and may also provide insight into the mathematics being addressed.

Diverse Learning Needs:

Essential Skills:

Learning Objectives: GEO.31.1: Define vertical angle, transversal, parallel lines, alternate interior angles, corresponding angles, perpendicular bisector, line segment, equidistant, endpoints, interior angles of a triangle, base angles of isosceles triangles, isosceles triangles, midpoint, median, intersection, opposite sides, opposite angles, diagonals, parallelogram, bisector, and converse.
GEO.31.2: Develop a process that demonstrates the logical order of properties to form a proof.
GEO.31.3: Arrange statements to form a logical order.
GEO.31.4: Identify measures of vertical angles, alternate interior angles, corresponding angles, measures of interior angles of a triangle, base angles of isosceles triangles, isosceles triangles, midpoint, and median.
GEO.31.5: Illustrate vertical angle, transversal, parallel lines, alternate interior angles, corresponding angles, perpendicular bisector, line segment, equidistant, endpoints, interior angles of a triangle, base angles of isosceles triangles, isosceles triangles, midpoint, median, intersection, opposite sides, opposite angles, diagonals, parallelograms, bisectors, and their properties.
GEO.31.6: Find the measure of the third interior angle of a triangle when given the measure of the other two interior angles.

Prior Knowledge Skills:

Define a right angle, Pythagorean Theorem, converse, and proof.

Select manipulatives to demonstrate how to compose and decompose triangles and other shapes.

Recognize and demonstrate that two right triangles make a rectangle.

Recognize polygons.

Alabama Alternate Achievement Standards

AAS Standard: M.G.AAS.10.31a When given an isosceles triangle and a measure of a leg or base angle, identify the measure of the other leg or base angle.
M.G.AAS.10.31b When given a parallelogram and the measure of one side or one angle, identify the measure of the opposite side or angle.