It may also be helpful to understand π (pi) and the circumference of a 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 ...

The circumference of a circle = \(\pi d\) or \(2\pi r\). Look at the sector of the circle shown below. To calculate the length of the arc, we need to know what fraction of the circle is shown.