Ancientpeoplesfromaroundtheworldknewaboutthespecialrelationshipbetweenacircle'scircumferenceanditsdiameter.π,thenumberrepresentingtheresultwhenacircle'scircumferenceispidedbyitsdiameter,hadbeenknownandusedonproblemsforthousandsofyears.Consequently,inordertocalculatetheareaofacircle,πisalsoused,area=πr2.
