Answer:

The circumference of a circle is the distance round the circle. It is about 3 times the length of the diameter

C = 3 x d

C = p x d where p (π) is 3.141 59…

For E.g the circumference of a bicycle wheel of diameter 66 cm is about 3 x 66 cm, which is 198 cm. More accurately, it is approximately 3.142 x 66 cm which is 207 cm to the nearest cm. The word circumference is also used for the boundary of a circle as well for the length of the boundary.