Polygons and Angles Relationship

• Polygons are plane closed figures made up of line segments.
• Poly = many. Gon = angles. (Translating to many-sided figure).
• Figure A is a polygon because it has line segments.

  
• Figure B is not a polygon because it does not have line segments.

  
• Figure C is not a polygon because of the intersection.

  
• Figure D is a polygon because it’s collinear.

  
• A polygon must be:

  1. Flat.
  2. Closed.
  3. Line segments.
• Convex —> No lines in the interior region of the polygon.
• Concave —> One of the lines lay on the inside, and a shape can be formed from it.
• When a polygon has congruent sides it’s called a regular polygon. If some sides are more than 180° then it’s an irregular polygon.