Is a traingle a regular polygon or a polygon?

This is a tautological question that does not have a proper answer. A regular polygon is one which has all its sides of equal length and all its interior angles of equal measure.

A regular polygon is a polygon whose sides are equal length and whose angles are all the same value. A non regular polygon is just the opposite of a regular polygon.

No, regular polygons are always convex and are shapes constructed using straight lines.concave polygons are irregular.

it has to be made out of strait lines so no curvesand it has to be closedlast it has to be flat it cant be 3D

A rhombus has four sides of equal lengths. So it is an equilateral polygon. But it is not an equiangular. It's angles are not equal in measure.