Pizza Pi

"Papa John’s pizzas come in four sizes: S, M, L & XL. But which is the best deal? We’ll calculate the area of each circle and the cost per square inch to find out."  This web site provides a slide show, lesson plan, and a student handout. Use the area of a circle to extend problem solving in real world math.

Standards & Objectives

Academic standards
GLE 0706.2.3
Develop an understanding of and apply proportionality.
GLE 0706.2.4
Use ratios, rates and percents to solve single- and multi-step problems in various contexts.
GLE 0706.4.3
Understand and use scale factor to describe the relationships between length, area, and volume.
Alignment of this item to academic standards is based on recommendations from content creators, resource curators, and visitors to this website. It is the responsibility of each educator to verify that the materials are appropriate for your content area, aligned to current academic standards, and will be beneficial to your specific students.
Learning objectives: 

Students will:

  • Given the diameters and prices of different pizzas, evaluate several methods of comparing their relative values
  • Use the diameter of a pizza to calculate its area
  • Calculate price per square inch as a unit rate and use it as a basis of comparison
  • Decompose a pizza’s area into “crust” (annulus) and “pizza” (circle) and represent those areas as percents

Lesson Variations

Blooms taxonomy level: 

Helpful Hints

Additional Material(s):

  • colored pencils (optional)