Pi or π is a constant whose value is the ratio of any given circle's circumference to its diameter.

It is approximately equal to 3.14159 in decimal.

There are also some exact representations of the value of pi:

- (Pi is the limit of the perimeter of a regular polygon with
*n*sides as*n*reaches infinity divided by the intended diameter*d*- by Archimedes)

- (Leibniz formula for pi)

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