Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Triangles

9-12

30 Minutes

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

TI Connect™

• ##### Accessories

TI Connectivity Cable

## Measuring Angles in a Triangle

#### Activity Overview

In this activity, students learn about the sum of the angles in a triangle. They understand triangles and their interior angles. NCTM Geometry Standard covered: Analyze characteristics and properties of 2- and 3-dimensional geometric shapes and develop mathematical arguments about geometric relationships.

#### 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
• Set up the TI-Navigator™ system
• See the attached PDF file for detailed instructions for this activity
• Print pages 7-8 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to your class.

• Draw a triangle using the Apps
• Label the vertices of the triangle
• Measure the interior angles of the triangle
• Find the sum of the angles of the triangle
• Move the vertex and measure the angles of the triangle and find the sum of its interior angles

• TI-Navigator activity:
• Use Screen Capture to identify problems with labeling
• #### After the Activity

Review student results:

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