Math
posted by Brianna .
The surface area of a golf ball is 8.92 in ^2. The surface area of a softball is 53.78. Find the ratio of the volumes of a golf ball to a softball. Surface Area = 4π r^2 and Volume = 4/3π r^3
I don't understand this problem, could someone please help me?

volume=4/3 PI r^3
ratio= (rgolf/rsoft)^3
now how do you get the radius?
SA=4PI r^2
r= sqrt (SA/4PI)= k*sqrtSA
so ratiovolumes= (k*sqrtSAgolf/ksqrtSAsoft)^3=
(sqrt (SAgolf/SAsoft)^3
= (sqrt (8.92/53.78))^3 
So is my answer 496.479489?