What are the name or type of polygon?

Answer 1

A polygon is a closed 2-dimensional shape whose boundaries are straight lines. These are its sides and a polygon can have 3 or more sides - with no maximum number.

A 3 sided polygon is a triangle and a 4-sided one is called a quadrilateral. For 5 or more sides, the names are of the form n-gon where n is the Greek prefix for the number of sides. Since the number of sides is limitless, there are infinitely many polygons and so infinitely many names. It is obviously not possible to give a comprehensive list.

See the link below for guidance on the prefices. However, you should use prefices for polygons with more than 12 sides only if you want to be unhelpful, obfuscatory or pretentious. If you wish to be communicative and helpful to your reader, it is much better (and wholly acceptable) to refer to a 17-sided polygon as a 17-gon rather than heptadecagon (and that's still a relatively easy name to decipher).