Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Circles

9-12

30 Minutes

• ##### Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition

TI Connect™

• ##### Accessories

TI Connectivity Cable

## Exploring the Diameter and Circumference of a Circle

#### Activity Overview

In this activity, students explore the relationship between a circles' circumference and its diameter which leads them to their own "discovery" of a value for pi. NCTM Geometry Standard covered: Analyze characteristics and properties of 2- and 3-dimensional geometric shapes and develop mathematical arguments about geometric relationships.

#### Before the Activity

• Install the Cabri™ Jr. App on the students' graphing calculators using TI Connect™, a TI Connectivity Cable, and the Unit-to-Unit Link Cable
• See the attached PDF file for detailed instructions for this activity
• Print pages 21-22 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to your class.

Follow the Activity procedures:

• Draw a circle
• Measure the diameter of the drawn circle
• Measure the circumference of the circle
• Calculate the ratio of the circumference to the diameter
• Alter the circle and calculate the ratio again
• #### After the Activity

Review student results:

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