Education Technology

Angle Bisectors and Medians of Quadrilaterals

Published on 06/09/2008

Activity Overview

In this activity, students will construct angle bisectors and medians in quadrilaterals and explore the properties that appear to be true for four-sided figures. They may find it necessary to review the definitions and properties of special quadrilaterals in order to construct the figures.

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 155 - 158 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 parallelogram and its four angle bisector
  • Drag the vertex and /or side of the original parallelogram and observe the new quadrilateral formed by angle bisectors
  • Construct the medians of a generalized quadrilateral
  • Construct the quadrilateral formed by the medians
  • Drag the vertices and\or sides to form a special quadrilateral and note what happens to the quadrilateral formed by the medians
  • Calculate the ratio of the area of the original quadrilateral to the area of the quadrilateral formed by the medians
  • After the Activity

    Review student results:

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