How to calculate PI number?

Pi (π) is one of the most important and

fascinating numbers in mathematics.

Roughly 3.14, it is a constant that is used to calculate the circumference of a circle from that circle's radius or diameter. It is also an irrational number, which means that it can be calculated to an infinite number of decimal places without ever slipping into a repeating pattern. This makes it difficult, but not impossible, to calculate precisely.

Measure the amount of times a radiant of a circle can stretch around a circle then divide it by two.