March 14, National Pi Day, honors 3.14 (Ï€) the ratio of the circumference of a circle. Whether you're challenging yourself to find how many decimal placements are actually in Pi (Ï€) or you're eating ...
CC0 Usage Conditions ApplyClick for more information. About two thousand years ago, a Greek scholar named Eratosthenes used some sticks, shadows and math to calculate the circumference of the Earth.