What Is the Formula for the Circumference of a Circle?

The formula for circumference of a circle is 2πr, where “r” is the radius of the circle and the value of π is approximately 22/7 or 3.14. The circumference of a circle is also called the perimeter of the circle.

If the radius of the circle is 14 centimeters, then the circumference is 2 x 22/7 x 14, which equals 88 centimeters. If the diameter of the circle is given, then the formula for circumference is πd, where d is the diameter. If the diameter of the circle is given as 21 centimeters, then the circumference is 22/7 x 21, which equals 66 centimeters.