# Activities

• • • ##### Subject Area

• Math: Geometry: Triangles

• ##### Author 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

3.2

• ##### Report an Issue

Triangle Inequality Theorem

#### Activity Overview

Given the measures of any three segments, will you always be able to make a triangle?

#### Objectives

• Students will identify the conditions necessary to build triangles given the lengths of 3 segments.
• Students will use the Triangle Inequality Theorem to determine whether a triangle can be formed when given 3 segments.

• triangle
• inequality
• segment
• conjecture

#### About the Lesson

This lesson involves building triangles from three segments. As a result students will:

• Manipulate given segments and make conjectures about the relationships between the lengths of the segments and the possibility of forming a triangle.
• Use randomly generated side measures and manipulate the corresponding segments to determine whether the combination of measures will form a triangle.
• Make and justify a conjecture describing the conditions that must be met to build triangles given segments of different length.