Answer: 1,512 cubic inches
Explanation:
To get the length of the inner side of the cube, we multiply the thickness by 2 and then, we subtract the result from the outer side of the cube.
In terms of equation:
(inner side) = (outer side) - 2(thickness)
Since the outer side is 12 inches and the thickness is 3 inches, then the inner side is given by
(inner side) = (outer side) - 2(thickness)
= 12 - 2(3)
(inner side) = 6 inches
Therefore, the amount of metal needed to smelt the cubic box is given by
(Volume of metal) = (outer side)³ - (inner side)³
= 12³ - 6³
= 1,728 - 216
= 1,512 cubic inches
