This figure shows a cube decomposed along the diagonal into
3 square pyramids
(the bottom square of the cube is the base of one pyramid, the square
face towards us is another base, and the square face on the right side is
which would explain why the
volume of a square pyramid is one-third the height times the base.
Are they congruent pyramids though?
To answer this question, use this pyramid net. Make 3 copies. Do they fit
together along the diagonal?