# Activities

• ##### Download

• • ##### Subject Area

• Math: Geometry: Triangles

• ##### Author 6-8

60 Minutes

• ##### Device
• TI-73 Explorer™
• ##### Other Materials
This is Activity 2 from the EXPLORATIONS Book:
Discovering Mathematics with the TI-73: Activities for Grades 7 And 8

The following materials are required for this activity:
• Student Worksheet
• 12 six-inch straws
• 40-50 twist ties
• A pair of scissors, a marker, and a ruler

TryAngle?

#### Activity Overview

In this activity, students investigate properties of triangles by randomly generating possible side lengths for triangles. They learn to determine if three line segments can form a triangle. They also learn to classify triangles as acute, obtuse, right, scalene, isosceles, and equilateral triangles. They gain an understanding of the Pythagorean theorem.

#### Before the Activity

• See the attached PDF file for detailed instructions for this activity
• Print pages 13 - 18 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to the class.

Follow the Activity procedures:

• Randomly generate 3 numbers between 1 and 6 using the roll dice program on the calculator
• Use the three numbers as side lengths, cut straws to form these lengths and create a triangle
• Keep a tally of the three numbers that could be used to make triangles and those that could not make a triangle
• Classify triangles as equilateral if all sides are congruent, as isosceles if two sides are congruent, and as scalene if no two sides are congruent
• Classify the triangles as acute if all angles of the triangle are below 90 degrees
• Classify the triangle as obtuse if triangle has an angle greater than 90 degrees and has 2 acute angles
• Classify triangles as right triangles if the triangle has an angle of 90 degrees and two acute angles
• Test for a Pythagorean triplet using the side lengths of different triangles and find the right, acute, and obtuse triangles
• Combine class data and create a list of all triangles (28 triangles) possible with a side of 1", 2", 3", 4", 5", and 6"
• Use the triangle inequality rule to test the triangles
• Classify the triangles by their sides and angles
• #### After the Activity

Students will complete the Worksheet and analyze the results.

Review student results:

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