Today is Pi Day, so named because the first three digits of pi are 3.14 and the date is March 14—or 3/14 in the format used in the United States. Yes, on most other parts of Earth today is also March ...

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 ...

Does the date March 14 ring a bell with you? Best known as Pi Day, 3/14 is the celebration of the number that begins with 3.14159 … and never ends. Pi (π) is the ratio of a circle’s circumference to ...