What is a Polygon?

A polygon is a closed figure composed of three or more line segments
The line segments that make up the polygon are called sides
A point where the line segments intersect is called a vertex
Sides of a polygon can only intersect at their endpoints
The first example is not a polygon because its sides intersect at a point that is not an endpoint
The second example is not a polygon because it has a curved side
The third example is not a polygon because it is not closed

1. Our example polygon is made up of 4 line segments, so it has 4 sides
1. Sides cannot cross anywhere except for at their endpoints
1. Polygons have special names based on how many sides they have
1. Polygons have special names based on how many sides they have
2. You can name a polygon with any number of sides by the number of sides it has
3. So if a polygon has 13 sides, you could call it a 13-gon
1. The first "yes" example is an example of a pentagon
2. The second "yes" example is an example of a hexagon
3. The first "no" example has sides that intersect at a point that is not an endpoint, so it is not a polygon
4. The second "no" example has a curved side, so it is not a polygon
5. The third "no" example is not closed, so it is not a polygon

Definition: Polygon