Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Circles

9-12

30 Minutes

• ##### Device
• TI-Nspire™
• TI-Nspire™ CAS
• ##### Software

TI-Nspire™
TI-Nspire™ CAS

• ##### Other Materials
Several varied sizes of circular objects:
• cans, lids, bowls, cups, coins
• Several tape measures

## Diameter and Circumference Relationship

#### Activity Overview

A short activity that helps to demonstrate the relationship between diameter and circumference.

#### Before the Activity

Put the students in groups. Groups of 2 or 3 work best. Each group will need a tape measure and several circular objects to measure.
Before they begin, discuss how to best measure the diameter and circumference of an object. Stress that they should be consistent in their methods.

#### During the Activity

The students will follow the step by step instructions on the handout to record the data and find the slope of the line formed.
They should use the data that they collected rather than the numbers that are used as examples on the worksheet.

#### After the Activity

Use the information gathered to determine the formula for the circumference of a circle, given the diameter.