In this situation, the equation that you would be using is A = 2
rh+2
r²
You have the Diameter: 18, and the height: 28
Since you have to use the radius in the equation, you would divide the diameter by 2 to get the radius, since the radius is half of the diameter.
The radius would be 9.
You will plug in 9 in R, and plug in 28 in H. Your equation would look like this:
2
(9)(28)+2
(9)²
When you solve the equation, you would get 2092.3 cm. Then you would round it to the nearest whole.
The surface area of the cylinder is 2092 cm²