All the edges of a regular polygon have the same length, and all the angles are congruent. If a regular polygon has n edges, it is an n-gon. By an earlier formula, each interior angle measures 180×(n-2)/n. This approaches 180 for large n, but never equals 180. Therefore the shape is convex.
Starting with 3 edges, the first few n-gons are as follows:
equilateral triangle, square, pentagon, hexagon, heptagon, octagon, nonagon, decagon.