Education Technology

# Activities

• ##### Subject Area

• Math: PreAlgebra: Geometry

9-12

60 Minutes

• ##### Device
• TI-30X IIB
• TI-30X IIS
• TI-34 II Explorer Plus™
• ##### Other Materials
This is Activity 10 from the EXPLORATIONS Book:
Math Investigations with the TI-30X IIS: Activities for Secondary Mathematics

You will require the following materials for this activity:
• 3 X 5 index cards
• Coordinate grid paper

## From a Distance...You Can See It!

#### Activity Overview

Students find the distance between points using common fractions and decimals, with the concepts of midpoint and distance. They also learn to solve problems using the Pythagorean theorem.

#### Before the Activity

• See the attached PDF file for detailed instructions for this activity
• Print pages 97 - 100 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to the class.

• Draw a line segment and label three midpoints as described
• Use the calculator to determine the measure of each half segment

• Plot a trapezoid on a grid paper
• Mark and label the midpoints of three sides
• Use the midpoint formula to find the midpoint of the fourth side
• Use the distance formula to determine the length of the fourth side

• Draw a diagonal along a 3" x 5" card, forming two right triangles
• Draw an altitude from the right triangle to the hypotenuse of one of the right triangles, forming three triangles
• Measure the lengths of the sides of the three triangles and record the values in a table
• Compare side lengths and check if they confirm to the Pythagorean theorem
• #### After the Activity

Students complete the Student Activity pages and solve problems.

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