# ALEX Classroom Resource

## Grade 8 Mathematics Module 2, Topic B: Sequencing the Basic Rigid Motions

Classroom Resource Information

Title:

Grade 8 Mathematics Module 2, Topic B: Sequencing the Basic Rigid Motions

URL:

Content Source:

EngageNY
Type: Lesson/Unit Plan

Overview:

Module 2, Topic B is a critical foundation to the understanding of congruence. All the lessons of Topic B demonstrate to students the ability to sequence various combinations of rigid motions while maintaining the basic properties of individual rigid motions. Lesson 7 begins this work with a sequence of translations. Students verify experimentally that a sequence of translations has the same properties as a single translation. Lessons 8 and 9 demonstrate sequences of reflections and translations and sequences of rotations. The concept of sequencing a combination of all three rigid motions is introduced in Lesson 10; this paves the way for the study of congruence in the next topic.

Content Standard(s):
 Mathematics MA2015 (2016) Grade: 8 17 ) Understand that a two-dimensional figure is congruent to another if the second can be obtained from the first by a sequence of rotations, reflections, and translations; given two congruent figures, describe a sequence that exhibits the congruence between them. [8-G2] NAEP Framework NAEP Statement:: 4G2e: Match or draw congruent figures in a given collection. NAEP Statement:: 8G2e: Justify relationships of congruence and similarity and apply these relationships using scaling and proportional reasoning. NAEP Statement:: 8G3c: Represent problem situations with simple geometric models to solve mathematical or real-world problems. NAEP Statement:: 8G3f: Describe or analyze simple properties of, or relationships between, triangles, quadrilaterals, and other polygonal plane figures. Alabama Alternate Achievement Standards AAS Standard: M.AAS.8.17- Given a geometric figure and a vertical or horizontal translation and reflection across a vertical or horizontal line, identify the components (lines/sides, angles) of the two figures that are congruent (limited to non-equilateral rectangles and triangles).
Tags: congruent, figure, properties, reflections, rigid motions, rotations, translations, twodimensional