An 8 sided octagon has 8 vertices
I think you mean an octagon, in which case it has 8 sides.
A pentacontagon has 50 vertices (not vertices's!).
16 vertices.16 vertices.16 vertices.16 vertices.
8 vertices
Eight vertices
it has 30 vertices
5 vertices
11 vertices
8 vertices
There are 10 vertices.
4 vertices
8 vertices.