TITLE: Is *njwildberger* wrong about area and circumference of a circle?
QUESTION [6 upvotes]: In this video, njwildberger says that the area and circumference of a circle are proof-less theorems. But I heard that we can derive both the area and circumference of a circle using calculus? So are the area and circumference of a circle proof-less theorems?

REPLY [10 votes]: There is no such thing as a proof-less theorem. I just watched the video and he's fast and loose with his terminology. What he means to say is that these theorems are presented to high school students without proof. He doesn't mean there is no proof. Then again, lots of things are presented to students without proof early in their education, so that's not really saying much.