Area of a square

To work out the area of a square, take one side, and multiply it by itself, as all sides on a square are equal.

Area of a rectangle

To work out the area of a rectangle, multiply one of one of the sets of parallel sides, by one of the other set of parallel sides.

Area of a circle

To work out the area of a circle, use the formula

C = Circumference
R = radius
D = Diameter

${\displaystyle \mathrm {Area} =\pi r^{2}.\,}$.

In the equation, r, the radius is the line from the circumference of a circle (the outside) to the center point.