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.
There is no specific name. It just known as a 380-gon.
name of 4000 sided polygon
The name of a 600 sided polygon is Hexcosiagon.
The name of a 200 sided polygon is dihectagon.
A dodecagon is a 12 sided polygon
The name of a sided polygon is Octaconpentagon.
The name of a 51 sided polygon is Pentaconhenagon. The name of a 52 sided polygon is Pentacondigon. The name of a 53 sided polygon is Pentacontrigon. The name of a 54 sided polygon is Pentacontetragon. The name of a 55 sided polygon is Pentaconpentagon. The name of a 56 sided polygon is Pentaconheptagon. The name of a 57 sided polygon is Pentaconhexagon. The name of a 58 sided polygon is Pentaconoctagon. The name of a 59 sided polygon is Pentaconenneagon.
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 9 sided polygon is nonagon.
The name of a 113 sided polygon is Tridecahectagon.
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.