Answer:
base = diameter
Explanation:
if the surface area of the cylinder is 800...
the height is 15... then the formula must be 3.14 x 15 x R2
r squared is supposed to be the square of the radius of the cylinder\
conclusion: 3.14 x 15 x R2 is 800_
so.multiply then..find the radius and add the answer you get to find the diameter ..