The surface area formula for any sphere is 4(pi)(radius)^2
The radius is half of the diameter.
18.6 / 2 = 9.3
So, plug into the formula and solve.
4(3.14)(9.3)^2 = 1086.3 mm^2
Whats the question? how many is she buying? or how many can she afford?
Answer:
okay thank you for free points