Question

How do I find the volume of a second cube if all I have is the volume and width of one and only the width of the other?

The width of one is 1ft, and 6 is the volume.
The second has a width of 3. It has the same Length and depth but I don't know it.

Answer 1

hmm in short

you know the sides, the corresponding sides

so the volume of each, will correspond to the "cube" of the corresponding sides
or \(\bf \cfrac{3^3}{1^3}=\cfrac{x}{6}\)

Answer 2

so is a matter of using similar shapes
you'd use the corresponding sides ratio

3/1 and equate the "cube" of them, to the given volumes