Education Technology

Properties of Parallelograms

Published on 06/09/2008

Activity Overview

In this activity, students go through the process of proving a quadrilateral to be a parallelogram. They understand the various characteristics of a parallelogram.

Before the Activity

Install the Cabri™: Jr. App on the students' graphing calculators using one of these two methods:

  • TI-Connect™,  a TI Connectivity Cable, and the Unit-to-Unit Link Cable
  • TI-Navigator™  "send to class" feature
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 37 - 39 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to your class.

    Follow the Activity procedures:

  • Construct a parallelogram
  • Find and label the lengths of all the sides
  • Observe that the opposite sides are congruent
  • Alter the parallelogram and check this relationship
  • Find and label the measure of all the angles
  • Alter the parallelogram and observe that the opposite angles stay congruent
  • Note that the consecutive angles are supplementary
  • Drag the vertex and verify if this relationship is maintained
  • Construct diagonals and determine the point of intersection
  • Measure the distance between the point of intersection of the diagonals and the vertices of the parallelogram
  • Observe that the diagonals bisect each other
  • Note that if a quadrilateral is a parallelogram, then its opposite sides are congruent, opposite angles are congruent, consecutive angles are supplementary, and diagonals bisect each other
  • After the Activity

    Review student results:

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