Illustration of an icosahedron.

Icosahedron

Illustration of an icosahedron.

Illustration of the bottom part of an icosahedron. The base consists of a regular pyramid, upon which equilateral triangles are inserted to form the next section of the icosahedron.

Part of an Icosahedron

Illustration of the bottom part of an icosahedron. The base consists of a regular pyramid, upon which…

Illustration of the steps to a construction of an icosahedron. The base consists of a regular pyramid, upon which equilateral triangles are inserted to form the next section of the icosahedron, followed by another pyramid.

Partial Construction of an Icosahedron

Illustration of the steps to a construction of an icosahedron. The base consists of a regular pyramid,…

Illustration of a frustum of a pentagonal pyramid (including cross-section).

Frustum of Pentagonal Pyramid

Illustration of a frustum of a pentagonal pyramid (including cross-section).

A diagram of a five-sided pyramid with a pentagonal base and five edges coming to a vertex.

Pyramid Diagram

A diagram of a five-sided pyramid with a pentagonal base and five edges coming to a vertex.

Illustration of an inverted pentagonal pyramid. It is pyramid with a regular pentagon for its base.

Inverted Pentagonal Pyramid

Illustration of an inverted pentagonal pyramid. It is pyramid with a regular pentagon for its base.