A 38-sided polygon would be named a triacontaoctagon.
A five sided polygon is called a pentagon because pentagon means five sided polygon I think.
Tricontagon
A million-sided polygon is called a megagon.
A 12-sided polygon is called a dodecagon.
A 20-sided polygon is called an icosagon.
an irregular polygon
A five sided polygon is called a pentagon because pentagon means five sided polygon I think.
Tricontagon
Providing that it is a regular 38 sided polygon then each interior angle will measure: 170o31'34.74''
A 12-sided polygon is called a dodecagon.
A 20-sided polygon is called an icosagon.
A 25 sided polygon is called a icosikaipentagon.
A 14 sided polygon is called a tetradecagon.
A 90-sided polygon is called an enneacontagon.
A 24 sided polygon is called a icosikaitetragon.
A million-sided polygon is called a megagon.
A five-sided polygon is called a pentagon.