# Activities

• • • ##### Subject Area

• Math: Geometry: Similarity and Proportion

• ##### Author 9-12

40 Minutes

• ##### Device
• TI-84 Plus
• TI-84 Plus Silver Edition

## Exploring Triangle Proportions Using Cabri Junior 2.0

#### Activity Overview

Students will construct a triangle, the segment joining the midpoints of two sides, take measurements of angles and sides to make conclusions and complete the theorem by discovery.

#### Before the Activity

The students will be exploring the similarity theorem: If a line segment joins the midpoints of two sides of a triangle, the segment is parallel to the third side and is half the length of the third side.

#### During the Activity

Students will construct a triangle, the segment joining the midpoints of two sides, take measurements of angles and sides to make conclusions and complete the theorem by discovery

#### After the Activity

Review student results:

• As a class, discuss questions that appeared to be more challenging
• Re-teach concepts as necessary