Circumference of circle formula: The correct way to find the perimeter

The correct way to find the perimeter of a circle is to calculate it using the formula C = 2π × r . If the diameter or radius of a circle is known circumference of the circle can be easily calculated. The ratio of Circumference to the Diameter of a circle is always a constant and that is π. Master the circumference of a circle -get formulas , solved examples, and key tips with Vedantu. Learn fast and boost your math skills! Learn how to calculate the circumference of a circle using radius or diameter, and see the derivation of the formula . Find solved examples and practice problems with answers. What is the formula for the circumference of a circle ? The circumference (C) of a circle is the distance around it. It's calculated using either C = 2πr (where 'r' is the radius) or C = πd (where 'd' is the diameter). 2.