The name of a 12 sided polygon is Dodecagon.
A 8 sided polygon is called a octagon.
The name of a 99 sided polygon is enneacontaenneagon.
The name of a 19 sided polygon is enneadecagon.
The name of a 15 sided polygon is Pentadecagon.
I find the name "30-sided polygon", "40-sided polygon", etc. just fine.
The name of a 12 sided polygon is Dodecagon.
A 8 sided polygon is called a octagon.
name of 4000 sided polygon
The name of a 18 sided polygon is Octadecagon.
The name of a 99 sided polygon is enneacontaenneagon.
The name of a 8 sided polygon is Octagon.
The name of a 19 sided polygon is enneadecagon.
The name of a 15 sided polygon is Pentadecagon.
The name of a 7 sided polygon is Heptagon.
The name of a 9 sided polygon is Nonagon.
The name of a 17 sided polygon is Heptadecagon.