How do you figure square feet using a circumference?

Answer 1

Square feet are a measure of area, and the area of a circle is usually given by the equation:

a = πr2

The circumference of a circle is given with the equation:

c = 2πr

To find the area of the circle given only it's circumference, we can rearrange the circumference equation, solving it for r, and then substituting it into our radius equation in place of r.

c = 2πr

r = c / 2π

a = πr2

a = π(c / 2π)2

a = πc2 / 4π2

a = c2/π

So the area of a circle is equal to the square of it's circumference divided by pi.