Suppose the line containing each side is drawn. If any of the lines contain any point in the interior of the polygon then it is concave. Otherwise it is convex.
5.
Types of Polygons
A polygon with n sides is an n-gon.
A convex polygon in which all sides are congruent and all the angles are congruent is called a regular polygon.
6.
Perimeter, Circumference, and Area
The perimeter P of a polygon is the sum of the length of the sides of the polygon.
The circumference C of a circle is the distance around the circle.
The area A is the number of square unites needed to cover a surface.