The 2018 Pi Day is observed on 14 March
The Pi Day is observed every year on March 14 (3/14) across the world. It is an annual celebration of the mathematical constant ? (pi). Pi represents the ratio of a circle’s circumference to its diameter. It’s an important part of the foundation of mathematics, most importantly geometry, where pi is key to equations calculating the area of a circle, A = ?r2, and the volume of a cylinder, V = ?r2h.