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
• ##### Software

Cabri Geometry™
TI Connect™

• ##### Accessories

TI Connectivity Cable

• ##### Other Materials
• Calculator for instruction/demonstration
• USA TODAY newspapers

## Math TODAY: Ballooning Inside the Box

#### Activity Overview

Using the USATODAY® Infograph, "Ballooning Inside the Box," students will explore geometric relationships using similar triangles. Identifying triangles with two pairs of congruent angles to explore similarity properties of the triangles is an essential part of this activity.
Students will learn what happens to the ratios of corresponding sides of a variety of similar triangles.

#### Before the Activity

Provide one graphing calculator for each student. Each student should have a copy of the corresponding student activity sheet. Provide each student with the following calculator file (AppVar) SIMILAR.

#### During the Activity

• Have the students link their calculators and share the AppVar as part of the class period on the previous day or during the beginning of the class period when you are going to use this activity. Insure that graphing calculators have been updated with latest versions of operating system and Cabri Jr.
• Go over the relationship between the angle of incidence and the angle of reflection so that the students will understand why the triangles formed are similar.
• Review opening an AppVars using Cabri Jr. with your class before starting the activity.
• Students can work individually or in groups to assist each other during the activity.
• Have students discuss their discoveries while they work to better understand the relationships.
• Before starting the AppVars, remind students to carefully read the opening screen and the activity pages.
• It will help students to draw a diagram of the problem before starting Activity 2.