ClipArt of pyramids with various bases. A pyramid is a solid geometric figure with a base that is a polygon and sides that are triangular in shape and meet at a common point at the top, known as the apex.

Illustration showing that the volume of 2 triangular pyramids, having the same trihedral angle of the…

The illustration of a rectangular pyramid unfolded by creating edges equal length to the base and meeting…

"Science has succeeded in classifying the thousands of known crystals in six systems, to each of which…

"This is a form composed of twelve isoceles triangular faces, each of which intersects two of the horizontal…

"It consists of four isoceles triangular faces which intersect all three of the crystallographic axes,…

"It consists of four isoceles triangular faces which intersect all three of the crystallographic axes,…

"It consists of four isoceles triangular faces which intersect all three of the crystallographic axes,…

Illustration of the intersection of a square pyramid and a plane.

Illustration of the intersection of a square pyramid and a plane.

"This is bounded by four equilateral triangles and is identical with the regular tetrahedron of geometry."…

"The tetrahedron is a form composed of four equilateral triangular faces, each of which intersects all…

"The tetrahedron is a form composed of four equilateral triangular faces, each of which intersects all…

"If a positive and negative tetrahedron occured together with equal development, the resulting crystal…

Illustration of the intersection of a triangular pyramid and a plane.