The equation for height, width and length would equal the volume of a cube or a rectangular solid. Length times width equals area, then multiplying area by height equals volume.
There are several different formulas to determine the volume of different types of solid objects. For example, the volume of a cylinder is found by the equation V = pi * r^2 * h, where r is the radius of the end of the cylinder and h is the height of the cylinder. The volume of a sphere is V = (4 / 3) * pi * r^3, where r is the radius of the sphere.