In the equation

, a is the initial amount and b is the growth factor. So our initial amount is 30 and our growth factor is 8.3. Your correct choice for this is A.
EXPLANATION
If the height of the can is 4 inches and the diameter is 3--> radius=1.5 inches, the area is given by the following relationhip:

Replacing terms:

The approximate area is 37.7 in^2
Answer:
the nominator could be any number here