a balloon has a surface area of 113.1 inches^2. what is the diameter of the balloon?
a. 3
b. 6
c. 9
d. 12
e. 15

Question

a balloon has a surface area of 113.1 inches^2. what is the diameter of the balloon?
a. 3 
b. 6
c. 9
d. 12
e. 15

mathmale · Answer

I'd suggest you look up the formula for the surface area of a sphere.  This is a function of sphere radius, r.

Once you have this formula in front of you, solve it for the variable r.  This formula will involve surface area, so just replace A in the formula with the given surface area.

The problem asks you for the diameter (not the radius) of the balloon.  How will you answer that?