This document defines and classifies different types of polygons. It explains that a polygon is a two-dimensional shape with straight sides. Polygons are classified based on the number of sides, with examples given of triangles, pentagons, and polygons with up to 12 sides. The document also discusses concave and convex polygons, diagonals, the number of diagonals in a polygon, and the formula for calculating the sum of interior angles based on the number of sides.