Education Technology

# Activities

9-12

60 Minutes

• ##### Device
• TI-89 / TI-89 Titanium
• TI-92 Plus / Voyage™ 200

TI Connect™

• ##### Accessories

TI Connectivity Cable

• ##### Other Materials
This is Activity 10 from the EXPLORATIONS Book:
Geometric Investigations on the Voyage 200 with Cabri

## Building a Better Pet Run

#### Activity Overview

This activity is designed to make students realize that area of a rectangle changes for different widths.

#### Before the Activity

• See the attached PDF file for detailed instructions for this activity
• Print page 52 from the attached PDF file for your class
• #### During the Activity

Distribute the page to the class.

• Construct segment AB and place a point C on it
• Transfer the length of AC to another portion of the screen, and using this measure, construct a circle with radius FG (=AC)
• Draw perpendicular lines through both F and G
• Transfer the length of CB to F
• Construct a perpendicular line at the point of intersection of the second compass circle and the perpendicular through F
• Use the calculator to overlay quadrilateral FGHK, which is a rectangle
• Move point C along segment AB and note that the perimeter of the rectangle remains same, but its area changes
• Collect data for the width, area and perimeter of the rectangle for various positions of point C
• Set up a scatter plot of area versus width and observe that the plot has a parabolic pattern
• Perform a quadratic regression and determine the best-fit equation
• Solve the problem using the graph for the equation
• #### After the Activity

Review student results:

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