The document discusses the history and properties of pi (π). It describes how various ancient civilizations like the Babylonians, Hebrews, and Egyptians approximated pi. The Greeks studied pi's relationship to circles, cones, and cylinders. Over centuries, mathematicians like Machin, Euler, and Lambert improved approximations of pi and proved its irrationality. With modern computers, pi has been calculated to extreme accuracy. The document also notes how pi is