Pi is an old math formula used to calculate the area and circumference of a circle. It is a formula that is over four thousand years old, and was first used by the Babylonians and Egyptians. Babylonians calculated pi to be 3.125, while the Egyptians calculated it at 3.160484, which is more harder to use than 3.125. The letter "ÃÂ°" was chosen to represent 3.14 because it is the Greek letter that makes the "P" sound which stands for perimeter. This symbol was first used in 1709 by William Jones, who was working on a theory for pi.

In 500 B.C., pi is calculated at 3. In Syracuse in 250 B.C., Archimedes calculated pi at 3.1463. In A.D. 450 in China pi is calculated at 355/113. In A.D. 800 in Baghdad, pi is calculated 3.1416. Ludolph de Ceulen of Germany calculated pi to 35 places in the year 1600. Ramanujan from India created the formula for pi in the year 1900.

In 1990, a man from New York was able to calculate 2 billion digits of pi using the formula Ramanujan made.