Question

Check my answer?

Two similar cylinders have heights 6 inches and 15 inches.

What is the ratio of their surface areas?

A. 8 : 25

B. 9 : 10

C. 4 : 25

D. 9 : 25

I chose C.

Answer 1

There's also another one.

Gerry has two porcelain spheres. The radii of the spheres are in a ratio of 3 : 5.

What is the ratio between the volumes of the two spheres?

A. 27 : 125

B. 81 : 125

C. 3 : 5

D. 27 : 50

I chose B.

Answer 2

Whoops, I mean A.

Answer 3

Curved surface area, right?

Answer 4

It doesn't say

Answer 5

I don't think you can solve the first one without knowing the radius( be it CSA or TSA)
But the second problem's answer is NOT Option B.

Answer 6

The volume of a sphere is :
\[\frac{ 4 }{ 3 }\pi r ^{3}\]
Plug in the values and do it again.

Answer 7

I did that and I got 113.04 : 523.3, and that's not one of the answers

I must be doing something wrong.

Answer 8

both are right @Ber96

Answer 9

Oh, ok. Thanks @ganeshie8

Answer 10

you dont wanto find volume here. just you wanto find the ratio of volumes. so you're original ticks are right.

Answer 11

@ganeshie8 How's the second one correct? o_o

Answer 12

I meant to say that my second answer was A, not B.

Answer 13

yep ! A is right for 2nd q.

radii ratio = 3 : 5
volume ratio = 3^3 : 5^3

Answer 14

Oh, sorry. I thought you said the answer was B. x-|

Answer 15

It's alright, but thanks for your help, both of you :)

Answer 16

np :)