That not technically PI. It is a close approximation. PI = 3.14159265359 As you can see it is fine if you do not care about accuracy beyond 2 decimal places.
NASA only uses 15 digits of π for calculating interplanetary travel. At 40 digits, you could calculate the circumference of a circle the size of the visible universe with an accuracy that'd fall off by less than the diameter of a hydrogen atom
(via @rainmaker1973 in t witter)
(via @rainmaker1973 in t witter)