If a pyramid is sliced by a plane parallel to the base of the pyramid and that plane bisects the altitude of the pyramid, what percentage of the volume of the pyramid lies below the slicing plane?

Answer 1

the volumes of similar shapes is proportional to the cubes of the corresponding heights.

So the small pyramid cut off at the top is to the whole pyramid in the ratio of 1 : 8
So the bottom part is 7/8 of the whole or 87.5%