Education Technology


Published on 06/09/2008

Activity Overview

In this activity, students investigate the circumference of circles and learn about the irrational number Pi.

Before the Activity

  • Start the Geoboard App and format it
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 123 - 129 from the attached PDF file for your class
  • During the Activity

    Distribute the page to the class.

    Follow the Activity procedures:

  • Draw a circle with radius = 1/2 and find its perimeter
  • Draw and measure the diameter of the circle
  • Similarly draw four circles with radii r = 1, 2, 3, and 4
  • Calculate the circumference/diameter ratio and check using the formula in the calculator
  • Observe that the perimeter of the circle is given by 2πr, and the circumference divided by the diameter is always equal to π (3.1416)
  • Set up a scatter plot with the circumference versus diameter data
  • Guess the value of m in the equation for the line Y = mX
  • Graph the predicted value and adjust the value until a line of best fit is obtained
  • Note that Y = 3.1416X
  • After the Activity

    Review student results:

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