# Geoboards are used in this lesson on area and perimeter

Subject:

Math

7, 8

Title – Area & Perimeter using Geoboards
By – Andy Field
Primary Subject – Math
Secondary Subjects –
Grade Level – 7-8

OBJ: TLW apply the concepts of length, area, and perimeter to real world experiences.

Benchmarks: CGM 4

Procedure:

1. Students come in and complete bell work posted on board.

2. Pass out to each student 1 Geoboard, 5 rubber bands, and 1 page of Geoboard paper. Explain the unit of measurement we will be using, which is the distance between pegs on the board, referred to as one unit.

3. Check for student understanding of length by constructing horizontal and vertical line segments and having students determine length. Have students estimate length of diagonal segments. Relate Pythagorean theorem to right triangles if the class is ready. Use calculators if class is ready to derive irrational square roots for hypotenuses.

4. Transition lesson into perimeter. Determine perimeter of several polygons, then have students construct polygons given a perimeter.

5. Transition lesson into area. Make squares of various sizes and construct table comparing area to perimeter. Do the same with rectangles, then parallelograms.

6. If there is time, mirror the above activities with right triangles.

7. Relate the lesson to real life: We build yards and farms with rectangular patterns because rectangles have smaller perimeter to area ratios, e.g. You use less fence to have more yard.

8. Take up Geoboards. Make sure students put rubber bands back in the same pattern so teacher can quickly verify that all rubber bands are accounted for.

9. Check for understanding: Have students verbalize their own concepts of area, perimeter, and length.

10. Follow up lessons with centimeter graph paper: Draw figures of various areas. Determine the area of your foot.

EVALUATION: Informal Observation, Formal test (written)

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