Pi Day on 3/14 Celebrates Important Mathematical Constant with Pies

Pi Day celebrates the mathematical constant pi (3.14) on March 14 (3/14). It originated in 1988 at the Exploratorium science museum.

Pi is the ratio of a circle's circumference to its diameter, an infinite number with many practical uses in math, science, and engineering.

People mark Pi Day by eating pies - sweet dessert pies as well as savory pot pies and pizza pies. It's become a popular math-related holiday.

Pi helps calculate orbits, spacecraft communication, the scale of cylinders in refinery equipment, and more. NASA uses pi daily in space exploration.

Pi Day also honors Albert Einstein's birthday on March 14. The famous physicist behind the theory of relativity was born in 1879.