Education Technology

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