Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Triangles

9-12

45 Minutes

• ##### Device
• TI-Nspire™ CX/CX II
• TI-Nspire™ CX CAS/CX II CAS
• TI-Nspire™ Navigator™
• TI-Nspire™
• TI-Nspire™ CAS
• ##### Software

TI-Nspire™
TI-Nspire™ CAS

3.0

## Angle-Side Relationships

#### Activity Overview

Investigate some necessary conditions for creating a triangle.

#### Objectives

• Students will recognize that the largest angle in a triangle is opposite the largest side, the second largest angle is opposite the second largest side, and the smallest angle is opposite the smallest side.
• Students will recognize that given three segments and three angles that form a triangle, the triangle will be unique.

#### Vocabulary

• opposite sides
• opposite angles

#### About the Lesson

This lesson involves students manipulating three segments and three angles to build a triangle. As a result students will:

• Attach an angle to the longest segment; discover that the largest angle cannot be attached to the longest side to form a triangle.
• Build a triangle starting with the largest angle; discover there are restrictions on which side has to be opposite which angle.
• Recognize and generalize the relationship between the sides and the angles in a triangle.