Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Transformational Geometry

9-12

90 Minutes

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

TI Connect™

• ##### Accessories

TI Connectivity Cable

• ##### Other Materials
This is Activity 7 from the EXPLORATIONS Book:
Cabri™ Jr.: Interactive Geometry Activities and Investigations.

## Reflections in the Plane

#### 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.

• 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