The different types of polygons are discussed here.
In any polygon a pair of sides that are inclined to each other meet at a point. This point is called a vertex of the polygon. In the polygon there are as many vertices as there are sides.
The triangle has 3 sides and 3 vertices.
The quadrilateral has 4 sides and 4 vertices.
The pentagon has 5 sides and 5 vertices.
The hexagon has 6 sides and 6 vertices.
Related Concepts on Geometry - Simple Shapes & Circle