answers: a tetrahedron
context: shown on one lateral face. Facing the two gods, on the adjacent lateral face, is the deceased Ptahemwia, standing in an offering pose, facing three columns of hieroglyphs. Pyramidion A pyramidion (plural: pyramidia) is the uppermost piece or capstone of an Egyptian pyramid or obelisk, in archaeological parlance. Speakers of the Ancient Egyptian language referred to pyramidia as "benbenet" and associated the pyramid as a whole with the sacred benben stone. During Egypt's Old Kingdom, pyramidia were generally made of diorite, granite, or fine limestone, then covered in gold or electrum; during the Middle Kingdom and through the end of </s> to be a "regular" square pyramid, like the physical pyramid structures. A triangle-based pyramid is more often called a tetrahedron. Among oblique pyramids, like acute and obtuse triangles, a pyramid can be called "acute" if its apex is above the interior of the base and "obtuse" if its apex is above the exterior of the base. A right-angled pyramid has its apex above an edge or vertex of the base. In a tetrahedron these qualifiers change based on which face is considered the base. Pyramids are a class of the prismatoids. Pyramids can be doubled into bipyramids by adding a </s> the apex, provided that "h" is measured as the perpendicular distance from the plane containing the base. In 499 AD Aryabhata, a mathematician-astronomer from the classical age of Indian mathematics and Indian astronomy, used this method in the "Aryabhatiya" (section 2.6). The formula can be formally proved using calculus. By similarity, the "linear" dimensions of a cross-section parallel to the base increase linearly from the apex to the base. The scaling factor (proportionality factor) is formula_2, or formula_3, where "h" is the height and "y" is the perpendicular distance from the plane of the base to the cross-section. Since the
question: what do you call a pyramid with a triangular base