The area of a circle is found using the formula:
Area=πr2\text{Area}=\pi r^2Area=πr2
where rrr is the radius of the circle and π\pi π (pi) is approximately 3.14 or 227\frac{22}{7}722. If the diameter ddd is given instead of the radius, the area can be calculated using
Area=πd24\text{Area}=\frac{\pi d^2}{4}Area=4πd2
Alternatively, if the circumference CCC is known, the area can be found by
Area=C24π\text{Area}=\frac{C^2}{4\pi}Area=4πC2
The radius is half the diameter. To find the area, square the radius and multiply by π\pi π.
