SOLID GEOMETRY CONTINUES...

To be frank, I don't know how to define pyramid.

Parts of the Pyramid:

• Base
• Apex

Pyramid:

A pyramid is formed by connecting a base to an apex.

Actually Whenever we start with pyramid. All of us a sudden what we get in our mind is the Great pyramid of Egypt. But it is a type of pyramid.

We have different types of pyramid based on their bases. They are

• Triangular Pyramid
• Square Pyramid
• Pentagonal Pyramid

In detail when taken in account, the following gives

Triangular Pyramid:

It has four faces in which three sides are triangles and the base is also a triangle  where four vertices with six edges are present also known as tetrahedron.

Square Pyramid:

It has five faces in which four side faces are triangles and base is a square where five vertices and eight edge are present.

Pentagonal Pyramid:

This has six faces in which five side faces are triangles and base is a pentagon where six vertices and ten edges are present.

Again they are divided into two types based on apex position. They are 

• Right pyramid where the apex is straightly above the base.
• Oblique Pyramid  where it is not straight.

And then again into two types based on their Bases. They are

• Regular Pyramid when the base is a regular polygon.
• Irregular Pyramid when the base is a irregular polygon.

This is  what I know about Pyramid. These images are taken from Google images.