What is the Formula for Circumference?

The formula for circumference is C = d X pi, where C is the circumference, d is the diameter of the circle (2 X radius) and pi value is 3.14. For example: given: radius of circle is 3cm and circumference C= (2 X3) X 3.14 = 6 X 3.14 = 18.84 cm. You can find more information here: