Okay! A cylinders area is found by the following equation.
A = πr²h
We need to find the radius, which is half of the diameter. So the radius is 5.5 in.
A = π(5.5)²h
There is no provided height in the question you asked, but I will simplify as much as possible so if you have the height, you can simply plug it in!
A = 30.25πh in³
Remember π is the symbol for the irrational number 3.1415... Regardless, plug that into a calculator with the provided height and you’ll have your answer.
