Pre-Algebra Review Topic
The Meaning of PI
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Although we as teachers are always pressed for time, it is often advantageous to develop projects that students can work on to increase their understanding of the concepts we are trying to get across.

If you ask your students to explain what PI is, you will probably get an approximation for its value from most students.  You may wish to try the following exercise with your students so they can see where the number PI actually comes from.

Materials Needed

--- 3 or 4 cylindrical cans, canisters, paper-towel rolls, etc. of
     varying sizes for each group
--- string
--- rulers

Divide the students into groups.  Have the students measure the circumference of each can, and the diameter of each can, and record their measurements.

Then have them find the ratio of the circumference to the diameter for each set of readings.  

Record each group's ratios, and average the results to find the value of  .

Object

Circumference (C)

Diameter (D)

C/D

 Can #1 

      

Can #2

      

Can #3

      

Can #4