Education Technology

# Activities

• ##### Subject Area

• Math: Middle Grades Math: Geometry
• Math: Middle Grades Math: Measurement

6-8
College

60 Minutes

• ##### Device
• TI-73 Explorer™
GeoBoard App

## Relationships of Similar Polygons

#### Activity Overview

In this activity, students will use the TI-73 Geoboard APP to create similar polygons and to investigate the relationships between the lengths of their sides, their perimeters, and their areas.

#### Before the Activity

• Copy student worksheet pages
• RelationshipsSimilarPolygons.doc
• Install the Geoboard APP on a set of TI-73 calculators, one for each student
• Optional: Download 8 x 8 geoboard paper from the file below for recording purposes
• #### During the Activity

The attached document contains the steps of an investigative lesson using the Geoboard APP on the TI-73. Students will create multiple sets of similar figures and investigate the ratios of the lengths of their sides, their perimeters, and their areas to determine relationships that apply to any two similar figures. Questions that help the students understand the concepts are interjected throughout the activity. Students should determine that the lengths of the sides of similar polygons are in the same ratio as their perimeters and that the square of the lengths of the sides of the polygons are in the same ratio as the areas.

#### After the Activity

Students will be asked to apply their conjectures about the relationships of the lengths, perimeters, and areas to other sets of similar figures to see if their conjectures hold.