What is the formula for calculating the circumference of a circle?

The formula for calculating the circumference of a circle is C = 2πr, where C represents circumference, r represents the radius of the circle, and π (pi) is a mathematical constant approximately equal to 3.14.

This formula arises from the definition of circumference as the distance around the circle. The factor of 2 comes from the fact that the circumference can be thought of as two times the radius multiplied by pi. Furthermore, because the diameter of the circle is twice the radius (d = 2r), the formula can also be expressed as C = πd, linking circumference directly to diameter as well.

Thus, the given answer captures the relationship between radius and circumference accurately, establishing clearly how to find the distance around a circle based on its radius.