so assuming that each thing is 1.6:3 smaller
radius=1.6r to radius=3r
height=1.6h to height=3h
volume=pi times r^2 times height
1.6 3
pi times (1.6r)^2 times 1.6h to pi times (3r)^2 times 3h
pi times 2.56r^2 times 1.6h to pi times 9r^2 times 3h
pi times 4.096hr^2 to pi times 27hr^2
so the ratio is
pi times 4.096hr^2:pi times 27hr^2
divide both sides by pi
4.096hr^2:27hr^2
divide both sides by hr^2
4.096:27
answer is 4.096/27