**A six-sided polygon is called a hexagon.** A polygon is an enclosed figure with straight lines that do not cross over one another. Polygons do not necessarily have equal sides. A convex polygon has all angles pointing outward, but in a concave polygon, some angles can point inward.

The number of sides a polygon has determines its name, and the problem solver can work out names of polygons with many sides because the names are built in groups. For instance, for a 99-sided polygon, the problem solver uses the prefix enneacontakai for 90 and the suffix enneagon for nine, making enneacontakaienneagon. The numbers go even higher: the name for a polygon with 10,000 sides is myriagon.