Question

How would you find the surface area of a sphere if the circumference is 3pi

Answer 1

the surface area is 4*pi*radius^2, the circumference is 2*pi*radius, which in your case is 3pi so radius is 3/2 and then square the radius and multiply by 4 and pi :)

Answer 2

Find the radius r and plug the result into the expression for the sphere's surface area.
\[4*\pi*r^2\]
The ratio of the circumfrence to the diameter is equal to Pi. The diameter is twice the radius.
\[{3 \pi \over 2r} = \pi\]
r is 3/2 so the surface area is
\[4\pi({3\over2})^2 = 9\pi\]