What is the formula for the circumference of a circle?

The circumference of a circle is determined by the distance around the edge of the circle and is directly related to its radius and diameter. The formula that accurately describes this relationship is Circumference = 2 × π × radius.

This formula arises from the definition of π (pi), which is the ratio of the circumference of any circle to its diameter. Since the diameter is twice the radius, you can substitute diameter with 2 times the radius in the formula. This leads to the understanding that to find the circumference, you need to multiply the radius by 2 and then by π.

This is why the given answer is correct: it incorporates both the relationship between the radius and diameter, and it correctly utilizes π, ensuring that the correct measurement for the circumference is obtained.