You can put this solution on YOUR website! Volume is measured in "cubic" units. The volume of a figure is the number of cubes required to fill it completely, like blocks in a box.
V = length * width * height
Let x = measure of length * width * height
125 = x^3
Take the cube root of both sides of the equation.
cuberoot{125} = cuberoot{x^3}
5 = x
Your rectangular box is actually a square with length 5, width 5 and height 5.