The formula for the area of the circle is 𝑨 = π𝒓². To work out the area of a circle: Find the value of the radius. If the diameter is given, this must be halved.

…and you can see that the ribbon is just over 3 times the diameter of 1 circle. This number, called π (or pi), is approximately 3.14. You have shown that the circumference of a circle is π × ...