Hexagon.
There is no polygon with this name.
It is a quadrilateral.
HEXAGON
A polygon is a closed figure bounded by sides only. Triangle is the polygon of 3 sides and 3 vertices.
A quadrliateral (or quadrangle).
pentogon
The vertices are the "points" of a polygon.
A triangle has fewer than 4 vertices.
Divide the number of vertices by 3. Find the name of the polygon with that many sides. The prism has that polygon as a base. For example, a prism with 24 vertices. Divide by 3 so that is 8. An 8 sided polygon is an octagon. The name is an octagon-based prism.
An hexagon
triangular pyramid