Question

Activity: The Last Straw
5-6
Inequalities in One Triangle

Materials
• Drinking straws (pre-cut to various lengths), two for each pair of students
• Pipe cleaner (3-inch piece), one for each pair of students
• Centimeter rulers
Your teacher will divide the class into pairs and will give you and your partner two straws. Complete the table below with the data from Trials 1 and 2.
Trial 1
1. Measure the length of each straw in centimeters. Each straw represents the side of a triangle.

Answer 1

2. Put the pipe cleaner halfway into the end of one straw. Then, put the other straw on the other half of the pipe cleaner so that the straws are just touching. Bend the pipe cleaner to make an angle.
3. Open and close the angle along the ruler to determine two possible lengths for a third straw that could be the third side of a triangle.
4. Open and close the angle along the ruler to determine two lengths for a third straw that would not work for the third side of a triangle.
5. Let the length of the third side of the triangle be x. Write an inequality to show the longest and shortest possible lengths for the third side.
Trial 2
Trade straws with another pair of students and repeat the steps in Trial 1.
Summary
Prentice Hall Geometry • Activities, Games, and Puzzles
Copyright © by Pearson Education, Inc., or its affiliates. All Rights Reserved.
43
Work as a class with your teacher to determine the possible lengths for the third side of a triangle whose first two sides measure a and b.