Education Technology

Activities

• Subject Area

• Math: Geometry: Triangles

9-12

20 Minutes

• Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition

Triangle Midsegment Theorem

Activity Overview

Students will use Cabri Jr. to discover that the midsegment of a triangle is parallel to the third side and half the length of the third side.

Before the Activity

This activity can be done with beginners of Cabri Jr. Very little steps are needed and hints are given in the directions.

During the Activity

Distribute the attached worksheet. Review the definition of midsegment with the students. After the students draw the triangle with Cabri Jr. they should find the midpoint of two sides and draw a segement connecting the two midpoints to draw the midsegment. Then they will use the measuring tools to find the length and slope of both the midsegment and the third side (the side not include with the midsegment).

After the Activity

Use a pair share activity for students to verify the midsegment theorem. Invite a student to record it on the chalkboard to validate the students' work.