Throughout these problems, keep in mind that the equation of Surface Area for a Cylinder is 2πrh+2πr^2, where r = radius and h = height.
10. If the diameter is 6, then the radius is 3. Solve

:
That equals
282.74 cm approximately.
11.
The lateral surface area is just 2πrh. Let's substitute:

That equals 377 ft approximately.
12.

That equals 226.19 in approximately.
13.
If the diameter is 14, then the radius is 7.

That is 87.96 m approximately.
One of the best ways to learn is to check others' work. I may be wrong, so double-check yourself! Hope these help! ;P