Education Technology

# Activities

9-12

60 Minutes

• ##### Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition
• ##### Software

Cabri Geometry™
TI Connect™

• ##### Accessories

TI Connectivity Cable

• ##### Other Materials
This is Activity 9 from the EXPLORATIONS Book:
Exploring The Basics Of Geometry With Cabri

## Properties of Parallelograms

#### 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.

• 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