What is a 13-sided polygon?
a 13 sided polygon is called a Tridecagon
A 13 sided polygon is called a Tridecagon also a Triskaidecagon.
A polygon can be convex, which means Convex Polygon: A polygon that has all interior angles less than 180° Concave Polygon A polygon that has one or more interior angles greater than 180° A Complex polygon is neither convex or concave. A star polygon is an example of a complex polygon. If you look in google images, there are tons of pics of them.