Answer:
double the radius.
Step-by-step explanation:
Quadruple means 4 times. So you want to make the volume 4 times larger than it currently is.
This can be a little nasty because both numbers are the same.
V = 1/3 pi * r^2 * h
V = 1/3 3.14 * 4.8^2 * 4.8
V = 115.75296
Now if you double the radius, the volume becomes 4 times larger (or it should)
V= 1/3 * 3.14 * (9.6)^2 * 4.8
V = 463.012
Did that make the original volume larger?
115.75296 * 4 = 463.012 rounded.
