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 ...

Happy Pi Day! We celebrate pi on March 14 because 3-14 gives the first three digits of this famous number. But what’s the big deal about pi anyway? Why does it get a day? Well, for starters, it ...

SAN FRANCISCO -- Every March 14, mathematicians, scientists and math lovers around the world celebrate Pi Day, a commemoration of the mathematical sign Pi. That's because the date written numerically ...