Suffering from a stomach ache, Sir Cumference mistakenly drinks a magic remedy that transforms him into a dragon. His son, Radius, searches the castle for the cure. His quest for the magic number that is the same for all circles (pi) involves determining the diameter and circumference of various circular objects. Radius, while measuring a fruit pie, discovers the ratio of a circle's circumference to its diameter and the king is returned to his human form. From that point on, it is declared that pie with an e will be for eating and pi without an e will be the name of this number for all things round.--Ministry of Education website.

Mathematics grade 6 (2009). Mathematics grade 7 (2007).