How do I calculate the area of a circle

Caluculate the length of the radius, use the formula and then multiply the radius by itself and square it

- - Measure the circle's radius, or calculate it from some other

measurement of the circle that you have, such as its diameter.

- - Multiply the radius by itself.

- - Multiply the number you then have by "pi".

The result of that calculation is the area of the circle.

For "pi", take the number ' 3.14159 26535 89793 23846 ... '

and use as many of its decimal places as you need in order

to give your final answer the accuracy you require.

If you need the area correct to more than 20 significant figures,

then go to the internet, find a more accurate value for 'pi', and

use that one instead of the number that I have given you.