Education Technology

Middle Grades Math: Getting "A-Round" Area
by Texas Instruments

Updated on June 10, 2014

Objectives

  • Students will give an informal derivation of the relationship between the circumference and area of a circle

Vocabulary

  • circumference
  • area
  • pi
  • radius of a circle
  • parallelogram

About the Lesson

The lesson assumes students have a knowledge of the area formula for a parallelogram.

 

The lesson involves using sectors of a circle to form a parallelogram and, from this shape, investigating the area formula for a circle.

 

As a result, students will:

  • Use approximations for the circumference and radius of a circle.
  • Connect circumference and radius of a circle to the dimensions of the constructed parallelogram to develop an area formula for a circle.