sir cumference and the dragon of pi

Sir Cumference and the Dragon of Pi, published by Charlesbridge, written by Cindy Neuschwander and illustrated by Wayne Geehan (copyrights 1999), is an excellent math story suitable for elementary school students and adults (like me) and features a rhyming poem.
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Characters:
Sir Cumference, father
Lady Di of Ameter, mother
Radius, son and protagonist
Sym, brother
Geo of Metry, carpenter
Lady Fingers, cousin

Lady Fingers helps Radius make the pie.