# Pi

The greek letter is used in math as a geometric constant to represent a half-rotation in radians. The value of is naturally occuring and can be found by dividing the length of a circle’s circumference by the length of its diameter.

## Formulas

The constant also appears in geometric formulas related to the area and length of a circle.

## Tau

is closely related to the constant (tau). Where represents a half rotation in radians, represents a full rotation. This relationship is expressed below:

Tau | Concept

The circle constant τ (tau) is a number approximately equal to 6.283. The number is defined as the length of a circle's circumference divided by the length of its radius.