Select the correct answer.
The surface areas of two cubes are in a ratio of 1 : 9. What is the ratio of their volumes?
A 1:3
B. 1:9
C. 1:27
D. 1:81

C. 1:27

Step-by-step explanation:

a²/b²=1/9 => a=1 and b=3

a³/b³=1³/3³=1/27

C. 1:27

I agree with the other answer. Here's another way to see why the answer is 1:27

The surface areas are in ratio 1:9. This means we could have one square that has area 1 and the larger square is area 9.

The smaller square has sides of 1 and the larger square has sides of 3 (square root both area values).

Now if we had a cube that has dimensions of 1 unit, then the volume is 1*1*1 = 1 cubic unit. If we had a larger cube with dimensions of 3 units, then the volume is 3^3 = 3*3*3 = 27 cubic units. We can fit 27 smaller 1x1x1 cubes into the larger 3x3x3 cube.