Every year, Pi Day is celebrated on March 14 to commemorate the mostly used constant PI.

• Pi is an important symbol in Mathematics, Statistics and Physics. It is the ratio of the circumference of the circle to the diameter. The ratio is a constant of 3.14 PI.
• Pi Day falls on March 14. When the date is written in the format of month and date, it matches the first three digits of the Pi value. 
• The constant value of Pi was first calculated by Mathematician Archimedes of Syracuse.