How many vertices does a polyhedron hexagon have?

Answer 1

There is no such thing as a polyhedon hexagon.

A regular hexagon will tessellate and so it forms a plane (2-D) surface, not a 3-D shape. A 3-D shape with six faces is a hexahedron and this could be a triangular bipyramid with 5 vertices, a parallelepiped with 8 vertices, a pentagonal pyramid with six vertices. There are also other possible shapes.