Education Technology

Reflections in the Plane

Published on 06/09/2008

Activity Overview

Students' will learn how to perform a reflection using the Cabri™ Jr. application, and will explore the properties of reflections. This activity will extend the concepts of reflection to the coordinate plane.

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 45 - 48 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 a triangle and a reflection line
  • Reflect the triangle over the line of reflection and observe the relationship between the pre-image and the image
  • Drag the vertices and sides of the triangle, points on the reflection line and observe the relationship between the pre-image and image
  • Draw a triangle to reflect in the coordinate plane
  • Reflect the triangle across the x-axis and y-axis
  • Observe the relationships between the coordinates of the vertices of the pre-image and the corresponding coordinates of the vertices of the image
  • After the Activity

    Review student results:

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