CLEVELAND, OH (WOIO) - Pi Day is celebrated on March 14 each year to commemorate the irrational number of 3.141592653, meaning it cannot be written as a simple fraction.
The date, March 14, matches the first three numbers of pi: 3.14.
Pi, or π, is defined as the ratio of the circumference of a circle to its diameter. The symbol for Pi (π) was first used in 1737 by Swiss mathematician Leonhard Euler.
The fist Pi Day was in 1988 at the San Francisco Exploratorium.