The volume of a pyramid is \(\frac{1}{3}\) the volume of a prism of the same height. This demonstration actually shows a cube being decomposed into 6 pyramids, so each pyramid has volume \(\frac{1}{6}\) of the volume of the cube, or \(\frac{1}{3}\) the volume of a half-cube, which is the prism with the same height as the pyramid.
Click on graph to activate.