Commemorating Pi on Pi Day
In every circle, the circumference bears a constant ratio to its diameter. This constant is a transcendental number, denoted by the Greek alphabet π (Pi). Pi is approximately equal to 22/7 or 3.14159. Pi Day is observed on July 22 (or 22/7 in day/month date format). Pi Day is also observed on March 14 (3.14 in the month, date format) to commemorate the mathematical constant.