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….

Radians measure angles using the radius of a circle

Radians measure angles using the radius of a circle

Radians measure angles using the radius of a circle

Radians measure angles using the radius of a circle

Radians measure angles using the radius of a circle

Excel RADIANS function

Excel PI function