# Pyramid

A pyramid is a space figure that has any polygon for a base and triangles for all other faces.

### apex

The triangular faces meet at a point, or vertex, called the apex. The shape of its base names a pyramid:

### triangular pyramid

A triangular pyramid is a pyramid with a triangle-shaped base (as pictured above). If all the faces are equilateral triangles, it is known as a regular tetrahedron.

### square pyramid

A square pyramid is a pyramid with a square-shaped base (as pictured above).

### pentagonal pyramid

A pentagonal pyramid is a pyramid with a pentagonal base (as pictured above).

### rectangular pyramid

A rectangular pyramid is a pyramid with a rectangle-shaped base (as pictured above).

### Did you know?

The pyramids of Egypt served as tombs for ancient Egyptian kings. Pyramids are sometimes used in modern construction, as in the Louvre, a famous museum in Paris (pictured below).

See also tetrahedron.