Education Technology

Betweenness and the Sum of Parts

Activity Overview

In this activity, students' will explore the concepts of betweenness and the sum of parts visually, geometrically, and numerically for segments and angles using the Cabri® Jr. application. They will investigate how the sum of parts equals the whole.

Before the Activity

  • Install the Cabri Jr. App on the students' graphing calculators using TI Connect™, a TI connectivity cable, and the unit-to-unit link cables
  • Use the TI-Navigator™ to transfer the attached Cabri Jr. AppVar files to each calculator
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 3 - 5 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to your class.

    Follow the Activity procedures:

  • Use the AppVar to go directly to the exploration section
  • Draw and label a segment and a point on the segment
  • Measure the length of the segments
  • Change the position of the point and observe the change in the measures and note how they are related
  • Draw segments to form adjacent angles
  • Measure the angles formed
  • Change the position of the segment and observe the changes in the measures and note how they are related
  • After the Activity

    Review student results

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