The value of represents a half-turn inradiansand appears in many formulas relating to the circle.
The formula for thecircumference of a circleis 2r.
For example, the formula =DEGREES(PI()) returns 180.
PI Function
The Excel PI function returns the value of the geometric constant π (pi). The value represents a half-rotation in the radian angle system. The constant appears in many formulas relating the circle, such as the area of a circle.
