Answer: Ok So If you know the diameter or radius of a circle, you can work out the circumference. To begin with, remember that pi is an irrational number written with the symbol π. π is roughly equal to 3.14.
The formula for working out the circumference of a circle is:
Circumference of circle = π x Diameter of circle
This is typically written as C = πd. This tells us that the circumference of the circle is three “and a bit” times as long as the diameter."
