Two similar cylinders have heights 6 inches and 15 inches. What is the ratio of their surface areas? 8:25 9:10 4:25 9:25 i dont under stand how to do this

Question

Two similar cylinders have heights 6 inches and 15 inches.  What is the ratio of their surface areas?  8:25 9:10 4:25 9:25 i dont under stand how to do this

anonymous · Answer

The ratio of length is 6:15=2:5.
So the ratio of surface area would be $$2^2:5^2=4:25$$


Another solution (If you don't understand the first solution)
:Since they are similar diameter 1:diameter 2=height 1:height 2=6:15=2:5
Put Diameter 1 = 2x and Diameter 2 = 5x and find the surface area of both to find the ratio.

anonymous · Answer

oh I see thank you ! it makes sense now(: