Question

Two similar cylinders have heights 12 inches and 16 inches.

What is the ratio of their surface areas?

1 : 4

9 : 16

3 : 4

16 : 27

Answer 1

surface area of a cylinder is
\[2 \pi r h\]
r=radius of cylinder
h=height of cylinder

Answer 2

how do i do that without knowing the radius?

Answer 3

u have 2 Two similar cylinders that means
\[r_{1}=r_{2}\]

Answer 4

so i just make up a radius?

Answer 5

yes

Answer 6

okay so i got 226:301

Answer 7

i used 3 as the radius

Answer 8

thats right because 226:301=3:4
but u can do it in a better way
(surface of cylinder 1)/(surface of cylinder 2)=(2 pi r h1)/(2 pi r h2)=12/16=3/4
since 2 pi r=2 pi r

Answer 9

yeah i like that way...haha...but thanks :)

Answer 10

your welcome