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Cutting Pi

Source Institutions

    The Exploratorium

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Cutting Pi

In this activity, learners use a string and pair of scissors to find pi in the world all around them. Take the circumference of a round object with string and cut the string to that length. Then, see how many times the diameter of the round object can be cut from the circumference string. You'll find that regardless of the round object that you choose you will get a very similar answer each time. Activity includes step-by-step instructions with pictures, a video demonstration, and an explanation of the science behind the activity.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
5 to 10 minutes

Estimated Materials Cost:
1 cent - $1 per group of students

Age Range:
Ages 11 - adult

Resource Type:


Materials List (per group of students)

  • Circular or cylindrical object, such as a straight sided coffee cup, roll of tape, plateā€”or even a pie
  • String
  • Scissors
  • Optional: partner


  • Mathematics
    • Measurement
      • Circles


Components that are part of this resource:

Includes alignment to state and/or national standards

This resource is part of:

Access Rights:

  • Free access



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