Step by step instructions are given for the students to draw a segment, find the midpoint, and label the coordinates of the two endpoints and the midpoint. The students then record the data in a table for various segments. Based on the table students will discover how to find the midpoint of a segment from the coordinates of its endpoints.

This activity is designed for the novice user of Cabri Jr. Students may need instruction on how to start the application.

Distribute the attached document to the students. Encourage them to read the instructions through once before they begin the activity. The students should be able to follow the steps individually while the teacher walks around the room to assist as needed.

Have a table similar to the one in the document on the chalkboard. Ask for student volunteers to record one set of data in the table. Invite students to share their ideas about the midpoint formula. Use the data in the table to verify their findings.