Education Technology

Circles: Circumference and Area

Activity Overview

The idea of perimeter can be applied not only to polygons but to circles as well. The same idea can be said for the area of a circle.

Before the Activity

In trying to see the relationship that exists between the area of a polygon and a circle, imagine a circle that has been cut into triangles and placed in a regular fashion, one next to the other.
See the attached Activity PDF file(s) for detailed instructions for this activity.
Install the Cabri Geometry™ App on the students' graphing calculators following the attached instructions.

During the Activity

Follow the procedures outlined in the activity.
Students will:

  • Be able to use the graphing calculator and Cabri Geometry to understand the area and circumference of circles and the area and perimeter of a regular polygon.
  • After the Activity

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