Solution
For this case we have the following information:
D = 12m = 12/2 = 6m
h = 9m
And we want to find the surface are so we can use the following formula:
[tex]SA=2\pi rh+2\pi r^2[/tex]And replacing we got:
[tex]SA=2\pi\cdot6\cdot9+2\pi\cdot(6)^2=339.12+226.08=565.2m^2[/tex]Then the final answer is:
565.2 m^2