March 14, National Pi Day, honors 3.14 (π) the ratio of the circumference of a circle. Whether you're challenging yourself to find how many decimal placements are actually in Pi (π) or you're eating ...

Pi, a mathematical constant denoted by the Greek letter π, is the ratio of a circle's circumference C to its diameter d: π = C/d. The circumference of a circle is, in turn, equal to 2πr, where r is ...