Education Technology

# Activities

• ##### Subject Area

• Math: Precalculus: Rational Functions

6-8

60 Minutes

• ##### Device
• TI-73 Explorer™
• ##### Other Materials
This is Activity 14 from the EXPLORATIONS Book:
Activities for Algebra with the TI-73.

The following materials are required for this activity:
• Small mirror
• Meter stick

## The Closer I Get to You

#### Activity Overview

In this activity, students understand how to use the Laws of Reflection to find the heights of objects. They also gain an understanding of a rational function.

#### Before the Activity

• Set up the calculator for data collection
• See the attached PDF file for detailed instructions for this activity
• Print pages 199 - 205 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to the class.

• Tape one paper strip with 10 cm markings on the wall, and another on the floor, perpendicular to the first
• Draw a square in the center of a mirror and place the mirror on the floor such that the center of the square is 20 cm from the wall
• Record the position of the spotter when he sees the reflected image of the marking on the wall in the mirror
• Enter the height on the wall and the distance data as a list
• Set up a scatter plot
• Find a rational function to calculate the height of the student
• Determine where the spotter will have to stand to see the top of a classmate's head
• #### After the Activity

Students will complete the Data Collection and Analysis page and answer questions.

Review student results:

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