The length of the outside edge of a circle or a sphere.
Formulas
The calculate the circumference C of a circle as a function of its diameter d, we can use the equation : \({C} = πd\).
To calculate the circumference C of a circle as a function of its radius r, we can use the equation : \({C} = 2πr\).
Historical note
The term “circumference” is derived from the Latin word circumferre. This term was first used by Euclid in his work The Elements.