What is a concave polygon?

According to Math Open Reference, a concave polygon refers to a polygon or a plane figure that has one or more interior angles that measure greater than 180 degrees. This type of polygon is the opposite of the convex polygon.

Math Open Reference indicates that a concave polygon looks like a vertex that is pushed in toward the inside of the figure. One of the characteristics of a concave polygon is that some of its diagonals lie outside the polygon's interior space. Moreover, the area of a concave polygon can be calculated by using the same method of computing for the area of any other irregular polygons.