Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Triangles

6-8

60 Minutes

• ##### Device
• TI-73 Explorer™
• ##### Other Materials
This is Activity 7 from the EXPLORATIONS Book:
Shaping Middle Grades Mathematics: Activities for Geoboard and the TI-73

## Follow the Fence, Then the Hypotenuse

#### Activity Overview

In this activity, students use the Geoboard to determine the length of the hypotenuse of a right triangles.

#### Before the Activity

• Start the Geoboard App and format it
• See the attached PDF file for detailed instructions for this activity
• Print pages 77 - 81 from the attached PDF file for your class
• #### During the Activity

Distribute the page to the class.

• Using vertical and horizontal sides, draw squares with areas of 1, 4, 9, and 25 square units
• Find the length of the sides of the squares
• Note that the length of sides is found by taking the square root of the area and area is found by squaring the side
• Draw a rectangle to represent the pasture in the word problem and mark its diagonal
• Note that the diagonal divides the rectangle into two congruent right triangles, and is called the hypotenuse
• Draw a square in which the triangle's hypotenuse is the length of the square's side
• Find the area of the square by surrounding it with a larger square and subtracting the four triangular corners
• Calculate the area of the smaller square to be 25 square miles
• If the area of the square built off of the hypotenuse is 25 square units, the diagonal is 5 miles

• Draw the given triangle on the Geoboard, build a square on its hypotenuse, find the area of the square, and the measure of the triangle's hypotenuse
• #### After the Activity

Review student results:

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