Plane figure (2-D) made up of straight sides (line segments, not curved) that are all connected (closed, not open)
Examples and Non-Examples given in class:
(informal definition)- Polygon with an “indent” in it
(Formal definition)- Polygon with at least 1 interior angle measure of greater than 180º
(informal defintion)- Polygon that is not concave
(Formal definition)- Polygon whose interior angles all have measures less than 180º
Regular Polygon- polygon whose angles are all congruent, and sides are all congruent.
Named by their number of sides: