SOLUTION
The figure below is a cylinder
The surface area of a cylinder is given as
Curved surface area of the cylinder + area of the circular top and bottom. So we have
[tex]\begin{gathered} S.A=2\pi rh+\pi r^2+\pi r^2 \\ S.A=2\pi rh+2\pi r^2 \end{gathered}[/tex]
From the cylinder given
[tex]\begin{gathered} height\text{ }h=9\text{ }mi \\ radius\text{ }r=\frac{diameter}{2}=\frac{12}{2}=6mi \end{gathered}[/tex]
So applying the formula, we have
[tex]\begin{gathered} S.A=2\pi\times6\times9+2\pi\times6^2 \\ =108\pi+72\pi \\ =180\pi\text{ }mi^2 \end{gathered}[/tex]
Hence the answer is option D. 180π mi²
