Polygon: a closed shape of at least 3 line segments
Regular polygon: the line segments are congruent (the same) AND the interior angle measurements are congruent (the same)
Convex polygon: all angles under 180 degrees, if a line segment between 2 vertices is drawn, it will stay within the boundaries
Concave polygon: has at least one angle over 180 degrees, if a line segment is drawn between 2 vertices, it will leave the boundaries at least once; seems to "cave in" upon itself
Interior Angles: the angles on the inside of a polygon
Exterior Angles: the angle created between an extension of one side and the adjacent side of a polygon
This video explains the interior angles of convex polygons: what they are, how to add them up, and what they mean.
Just like in the interior angles video, the exterior angles video goes over the know-how on the exterior angles of polygons.
