This question needs to be answered, been stuck on this for 20 minutes.

Answer
B) 287.6cm²
Step-by-step explanation:
First you need the radius, since you have the diameter you have to divide it by 2 in order to get the radius (8.4 divided by 2 = 4.2) then use the formula A=2πrh and plug in the radius and your height (h) which is 10.9cm into the formula.