BioMedical Admissions Test (BMAT) Practice Test 2025 - Free BMAT Practice Questions and Study Guide

To calculate the circumference of a circle, the formula used is C = 2πr, where C represents the circumference and r represents the radius of the circle. This formula arises from the relationship between the diameter of the circle (which is twice the radius, or 2r) and the constant π, which relates the diameter to the circumference.

When you multiply the diameter (2r) by π, you arrive at the total distance around the circle, which is the circumference. Therefore, this formula quantifies how far you would travel if you followed the circle's edge all the way around.

The other options represent different mathematical relationships that do not apply to the calculation of circumference. For instance, C = πr² describes the area of a circle, not the circumference. C = 2r simply states a multiple of the radius without the proportional relationship to π, and C = r² also does not relate to circle measurements at all, rather it suggests a calculation of area in different contexts.