Answer:
A/B = 0.125
Step-by-step explanation:
Givens
r for Sphere A = 4
r for Sphere B = 8
Solution
Volume A = 4/3 pi r^3
r = 4
Volume A = 4/3 pi 4^3
Volume A = 4/3 pi 64
Note: there is no point in expanding the result. 4/3 and pi are going to cancel out when you set up the volume formula
Volume B = 4/3 pi * r^3
r = 8
Volume B = 4/3 pi * 8^3
Volume B = 4/3 pi * 512
Ratio A to B = 4/3 pi * 64 / 4/3 * pi * 512 Cancel 4/3 pi
Ratio A to B = 64/512
Ratio A to B = 1/8
Ratio A to B = 0.125
