Jake has two similar cylindrical pipes. The radius of the first cylindrical pipe is 5 cm. The circumference of the second cylindrical pipe is 20π cm.

The volume of the second cylindrical pipe is how many times greater than the volume of the first cylindrical pipe?
3
4
5
8

Question

Jake has two similar cylindrical pipes. The radius of the first cylindrical pipe is 5 cm. The circumference of the second cylindrical pipe is 20π cm. 

The volume of the second cylindrical pipe is how many times greater than the volume of the first cylindrical pipe?
3
4
5
8

asnaseer · Answer

Do you know what the radius of the second pipe is?

asnaseer · Answer

You should be able to work it out

anonymous · Answer

20pi = 2pir
r = 10
V = pi r r= 25pi
V = pi r r = 100pi

asnaseer · Answer

Can you work it out Blahh23?

anonymous · Answer

I don't have the radius of the second pipe.. I cant figure it out:(

asnaseer · Answer

You are given the circumference of the second pipe

anonymous · Answer

use the circumference equation C = 2pi*r

anonymous · Answer

i tried already... the happy helper.. How do we found the radius from the circumference i know there is a way i forgot though.

asnaseer · Answer

HappyHelper has given you the formula for the circumference - use that to work out the radius of the second pipe

anonymous · Answer

Oh i see. so the radius is 10 like her said up there.

asnaseer · Answer

yes - so now you know the radius has been doubled

anonymous · Answer

yes.. so that means that the thing must be 4 times larger??

asnaseer · Answer

for similar solids, if there linear dimension is increased by a factor of r, then it means their volume is increased by a factor of $r^3$

anonymous · Answer

but what is the height. we need that to find the volume ... ^ and idk what that means up there.....

asnaseer · Answer

in your case, the linear dimension (in this case the radius) was increased by a factor of 2.
So the volume increases by a factor of $2^3$

asnaseer · Answer

if two solids are 'similar' - it means all their linear dimensions are in the same ratio

asnaseer · Answer

so if the radius has increased by a factor of 2, it means the height is also increased by a factor of 2

anonymous · Answer

Oh okay........ so i should pick 2 as my answer correct?

asnaseer · Answer

no

asnaseer · Answer

do you know the formula for the volume of a cylinder in terms of its radius and height?

asnaseer · Answer

I am not here for medals.

anonymous · Answer

TO answer your question up there. yes its v=ttr^2h