math
posted by brianna on .
2 cylinders are proportional. The smaller cylinder has a radius of 4 cm. which is half as large as the radius of the larger cylinder.The volume of the smaller cylinder is 250 cubic cm. What is the approximate volume of the larger cylinder?

volume proportional to scale ratio cubed
250 * 8 = 2000
note, I did not have to work that out but here is why
vol = pi r^2 h
if R = 2 r
and H = 2 h
vol big = pi R^2 H = pi (2r)^2 (2 h) = 8 pi r^2 h