It's quite acceptable to call it a 38-agon but what's more important is knowing how to work out its properties.
The name of a sided polygon is Octaconpentagon.
The name of a 18 sided polygon is Octadecagon.
a 500 sided polygon is call a Pentahectagon... i believe
The name of a 56 sided polygon is Hexapentacontagon.
The name of a 700 sided polygon is Hexahectagon.
A 38-sided polygon would be named a triacontaoctagon.
icosihenagon= 21-sided polygon icosihenagon= 21-sided polygon
I would just call it an "800-sided polygon."
The name of a sided polygon is Octaconpentagon.
Tricontagon
Providing that it is a regular 38 sided polygon then each interior angle will measure: 170o31'34.74''
The name of a 18 sided polygon is Octadecagon.
The name of a 45 sided polygon is Tetraconpentagon.
The name of a 7 sided polygon is Heptagon.
The name of a 10 sided polygon is Decagon.
The name of a 8 sided polygon is Octagon.
The name of a 33 sided polygon is riacontakaitrigon.