Pi, represented by the Greek letter π, is one of the most important constants in mathematics. It is defined as the ratio of any circle's circumference to its diameter. No matter how large or small the circle, this ratio always equals approximately 3.14159. This fundamental relationship makes Pi essential in geometry, physics, and engineering.
Throughout history, many civilizations attempted to calculate Pi. The Babylonians approximated it as 3.125, while the Egyptians used 3.16. The Greek mathematician Archimedes made a breakthrough around 250 BC by using inscribed and circumscribed polygons around a circle. As the number of polygon sides increases, the perimeters approach the true circumference, giving increasingly accurate approximations of Pi.