Pyramid

A pyramid goes to a point

Triangular Based Pyramid

4 triangular faces

A traingular based pyramid which has 4 congruent equilateral triangles is an example of a Regular Tetrahedron

Square Based Pyramid

A square based pyramid which has 6 congruent squares is an example of a Regular Tetrahedron

Rectangular Based Pyramid

1 rectangular face and 4 triangular faces

A square based pyramid is a special example

Pentagonal Pyramid