When working with circles it is important to know the following definitions: The radius (r) of a circle is the distance from the centre to the outside of the circle. The diameter (d) of the circle ...

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. Substitute the value of ...