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Sir Cumference and the Dragon of Pi
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Book Review

Review by Jim Rahn

Sir Cumference and the Dragon of Pi:  A Math Adventure by Cindy Neuschwander

Illustrated by Wayne Geehan

Published by Charlesbridge Publishing, Watertown, MA 1999


bulletThe main characters in this children's story are Sir Cumference, Radius, Lady Di of Ameter, and  Geo of Metry.  These characters are weaved into an interesting adventure where Radius tries to cure his father, Sir Cumference of a stomach ache. The first cure turned his father into a dragon.  So he must continue to search for a solution which will bring his father back as a knight.    
bulletIn searching for a cure, Radius find a contain containing a poem about a circle's measure.  Not understanding the poem he seeks advice to understand it.  After receiving some advice he returns to his workshop and begins to measure some circles.  He measures the distance around each circle and the distance across each circle.      He continues to try to decipher the poem.  He fears that if he measures the wrong dose his father will remain a dragon forever.
bulletHow much should the dose be?  Just at the knights were arrive Radius noticed the dragon had formed a circle with his body.  Interpreting the poem, Radius measures diameter of the circle (7 feet) and the distance around the circle (22 feet).  Radius divides these two measuremtns and gets 3 1/7.  Radius gives the dragon 3 1/7 spoons full of the cure.  Immediately the dragon is returned to a knight. 
bulletIn celebrating the return of his father, the celebrate by eating pies.  He found that every time the outside measure was divided by the diameter the same number resulted:  3 1/7.  He named this special number pi, the word pie without the e.
bulletThis is a wonderful story to use when introducing students to circle measurements and the special number pi. 
bulletThis book would be appropriate for grades 4-8. 
bulletAvailable through Barnes and Noble