Question

The ratio for the lengths of radii of similar cylinders is 6 : 4. What is the ratio of their volumes?

I got 27:4

Answer 1

Am I correct

Answer 2

@SolomonZelman

Answer 3

hm no.
what's the equation for volume of cylinders?

Answer 4

pi(rsquared)(h)

Answer 5

good, now you plug 6 into that equation.
pi 6 squared h = 36 pi h

Answer 6

then, find volume of the other cylinder. Plug 4 into that equation
pi 4 squared (h) = 16 pi h

Answer 7

Now, you know that ratio can be written as fractions,right?

so 36pi h : 16 pi h

\[= \frac{ 36 \pi h }{ 16 \pi h }\]

Answer 8

now you can cross out pi and h on top and bottom

Answer 9

\[\large = \frac{ 36 }{ 16 } = \frac{ 9 }{ 4 }\]

so the ratio is 9 : 4

Answer 10

oh I get it thanks

Answer 11

anytime :D

Answer 12

can you help me with this one I don't get it.
If the scale factor between two similar solids is 2:5, then the ratio of their lateral areas is 4:10

Answer 13

is this a true/false question?

Answer 14

yeah it it.

Answer 15

I thought it was false... just a guess though

Answer 16

I found a good link :) hold on

Answer 17

okay thanks!

Answer 18

Took the pic, same with lateral area/surface area.

Answer 19

so, if you squared 2:5

the answer you get is 4 : 25

Answer 20

oh so lateral area is the same as surface area.

Answer 21

no, you use this equation for both surface area and lateral area.

They are not the same

Answer 22

oh okay thanks

Answer 23

Lateral areas does not include base's area.

Surface area includes BOTH sides + base areas.

Answer 24

You're welcomed :)