You can put this solution on YOUR website! the volume of the cube is 675 * 475 * 1200 cubic mm.
75% of that is 3/4 * 675 * 475 * 1200 cubic mm.
that would be equal to 288,562,500 cubic mm.
it's not really a cube.
a cube would have all 3 edges equal.
this is more like a rectangular prism.
