The "proper" name is trihectaoctacontagon. Most people, including mathematicians, will use 380-gon since that effectively communicates the size of the polygon. But, if you want to appear pretentious or be obfuscatory, by all means use the Greek prefices.
name of 4000 sided polygon
The name of a 200 sided polygon is dihectagon.
The name of a 600 sided polygon is Hexcosiagon.
there is no such thing as two-sided polygon.
The name of a sided polygon is Octaconpentagon.
The name of a 12 sided polygon is Dodecagon.
name of 4000 sided polygon
A 8 sided polygon is called a octagon.
The name of a 9 sided polygon is Nonagon.
The name of a 19 sided polygon is enneadecagon.
The name of a 17 sided polygon is Heptadecagon.
The name of a 8 sided polygon is Octagon.
The name of a 10 sided polygon is Decagon.
The name of a 14 sided polygon is Tetradecagon.
The name of a 99 sided polygon is enneacontaenneagon.
The name of a 18 sided polygon is Octadecagon.
The name of a 200 sided polygon is dihectagon.