Answer
The total surface area of the sphere is 144$\pi$ $cm^2$.
Work Step by Step
The diameter is twice the radius
So: d = 2r
12 = 2r
r = 6
The formula for the surface area of a sphere is 4 $\times$ $\pi$ $\times$ $r^{2}$
Substitute 6 for r to obtain:
A = 4 $\times$ $\pi$ $\times$ $6^{2}$
A = 4 $\times$ $\pi$ $\times$ 36
A = 144$\pi$