# ALEX Lesson Plan

## Finding Area with a geoboard

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This lesson provided by:
 Author: Lisa McNeill System: Covington County School: WS Harlan Elementary School
General Lesson Information
 Lesson Plan ID: 7412 Title: Finding Area with a geoboard Overview/Annotation: Students will use a geoboard to visualize the concept of square units, as well as measure with those units. They will also be able to visualize the formal formula to different polygons after working with this manipulative.
Associated Standards and Objectives
Content Standard(s):
 MA2015 (3) 22. Relate area to the operations of multiplication and addition. [3-MD7] a. Find the area of a rectangle with whole-number side lengths by tiling it, and show that the area is the same as would be found by multiplying the side lengths. [3-MD7a] b. Multiply side lengths to find areas of rectangles with whole-number side lengths in the context of solving real-world and mathematical problems, and represent whole-number products as rectangular areas in mathematical reasoning. [3-MD7b] c. Use tiling to show in a concrete case that the area of a rectangle with whole-number side lengths a and b + c is the sum of a x b and a x c. Use area models to represent the distributive property in mathematical reasoning. [3-MD7c] d. Recognize area as additive. Find areas of rectilinear figures by decomposing them into nonoverlapping rectangles and adding the areas of the nonoverlapping parts, applying this technique to solve real-world problems. [3-MD7d] MA2015 (4) 21. Apply the area and perimeter formulas for rectangles in real-world and mathematical problems. [4-MD3] Example: Find the width of a rectangular room given the area of the flooring and the length by viewing the area formula as a multiplication equation with an unknown factor.

Local/National Standards:

Primary Learning Objective(s):

Students will understand the concept of area. This includes facts such as: area is two dimensional, area is measured in square units, and base and height can be found in all regular polygons.

Preparation Information
 Total Duration: 31 to 60 Minutes Materials and Resources: geoboards and rubber bands for all students, (if possible; students can work in groups) overhead geoboard for teacher, rulers, 1/4 sheet of construction paper, scissors Technology Resources Needed: computer with internet connection Background/Preparation:
Procedures/Activities:
 1.)Pass out geoboards, rubber bands, construction paper sheets, and scissors. 2.) Allow students time to experiment with boards. Have students cut construction paper into a square that fit the individual squares of the geoboard. Explain to students that their construction paper square is their unit of measurement. Have students create a closed figure with their rubber bands on their geoboards. (Any figure will work) 3.)Allow students time to find the area of their polygon by using their unit of measurement.(construction paper square) **Some students will realize that they will have to half or quarter their figure in order to measure their entire polygon. After this initial measurement you will want to discuss with your class that in order to find the area you must cover the entire 'inside' with the unit of measurement. This may lead into a discussion of halves and quarters of their construction paper square. You may also want to allow students to tally every time they move their measuring unit in order to keep up with how many units they have used. 4.)Repeat previous steps as many times as needed until students begin to 'see' the area of their polygons. 5.)After students become comfortable with measuring with their construction paper unit, then you need to lead them into visualizing width and length. This should lead into a discussion of area equals length X width. This would be a good time to write the equation for area and lead into questions about what type of polygons this equation will solve. (rectangles and squares). 6.)Now lead students to make triangles and measure with their construction paper units. Lead them to visualize the formula for finding the area of a triangle. A=1/2BXH. Hopefully, students will begin to 'see' this as they have to half their construction paper measuring unit. 7.)Finally, after working several rectangles, squares, and triangles students will understand the concept of A=LXW and A=1/2BXH. You can lead students into further work with these formulas on paper without the manipulatives.
Assessment
 Assessment Strategies A good assessment for this lesson can be found at www.mathgoodies.com/lesson/vol1/area_rectangle.html This web site provides problems on area that will allow students to demonstrate their knowledge of area.
 Acceleration: Intervention: Students who are struggling with this concept may not be ready to move to paper and pencil problems involving area and may need to spend more time exploring with the geoboard.

Each area below is a direct link to general teaching strategies/classroom accommodations for students with identified learning and/or behavior problems such as: reading or math performance below grade level; test or classroom assignments/quizzes at a failing level; failure to complete assignments independently; difficulty with short-term memory, abstract concepts, staying on task, or following directions; poor peer interaction or temper tantrums, and other learning or behavior problems.

 Presentation of Material Environment Time Demands Materials Attention Using Groups and Peers Assisting the Reluctant Starter Dealing with Inappropriate Behavior
Be sure to check the student's IEP for specific accommodations.