Education Technology

Investigating Area Relationships

Published on 06/09/2008

Activity Overview

The interactive Cabri Jr. geometry application makes it easy to measure the area of triangles and quadrilaterals. In this activity, students will explore some interesting area relationships in quadrilaterals.

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 Cable
  • 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 163 - 166 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
  • Construct a trapezoid and its diagonals
  • Explore the relationship between the area of the triangle formed by diagonals
  • Investigate the relationship while dragging the vertices and sides of the trapezoid
  • Construct a parallelogram with a segment that divides the parallelogram into two trapezoids
  • Construct a square and its center
  • Construct a second conqruent square having a vertex at the center of the first square
  • Explore the relationship between the area of the square and the area of the region formed by the overlap of squares
  • After the Activity

    Review student results:

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