Similarity ratio (photo of problem attached)

Question

anonymous · Answer

attachment

anonymous · Answer

SA of cylinder: 2*pi*r^2 + 2*pi*r*h

hartnn · Answer

its given that they are similar, so their Surface areas will also be proportional,
with ratio, SA(small) /SA(large) = 20 pi y d^2 /125 pi y d^2
their similarity ratio (ratio of sides) will be then, 
$\large \sqrt{\dfrac{20\pi y d^2}{125\pi y d^2}}$

hartnn · Answer

Surface area is proportional to square of sides, hence to get ratio of sides from ratio of surface areas, we need to take square root

anonymous · Answer

all i get is 5/11 just tell me the answer so I can see how you got it. @hartnn

hartnn · Answer

just answer :O 
try to simplify this (ratio of surface areas) first, 
$\large {\dfrac{20\pi y d^2}{125\pi y d^2}}$

hartnn · Answer

what gets cancelled ?

anonymous · Answer

wouldnt they all get canceled except for the 20/125?

jhannybean · Answer

yep

hartnn · Answer

exactly!
and what does that simplify to ?

anonymous · Answer

4/25?? @hartnn

hartnn · Answer

yes! now just take the square root, because we need ratio of sides, not areas...

anonymous · Answer

ohh so its 2:5?

hartnn · Answer

yup :)

anonymous · Answer

YAAAAY thank you sooo much! @hartnn

hartnn · Answer

welcome soo much ^_^