"which is π times the radius, squared" The comma in your expression of the formula implies the wrong calculation IMHO . The formula is "pi times R to the second power" which is executed as: pi times (radius squared). You have to square the radius before multiplying by pi. Your original statement gives the impression of: "(pi times radius), squared" which gives a vastly different and incorrect answer. Perhaps to be more clear express as: "π, times the radius squared" Cheers
Also reminds me of the scene from the Beverly Hillbillies, when Jethro is explaining to Uncle Jed what he learned in school that day: Jethro: "I learned pi R squared" Uncle Jed: "Pies ain't square boy, They's round. Corn bread's square"