2PolygonsDefinition:A closed figure formed by a finite number of coplanar segments so that each segment intersects exactly two others, but only at their endpoints.These figures are not polygonsThese figures are polygons
3Classifications of a Polygon Convex:No line containing a side of the polygon contains a point in its interiorConcave:A polygon for which there is a line containing a side of the polygon and a point in the interior of the polygon.
4Classifications of a Polygon Regular:A convex polygon in which all interior angles have the same measure and all sides are the same lengthIrregular:Two sides (or two interior angles) are not congruent.
6Convex Polygon Formulas….. Diagonals of a Polygon:A segment connecting nonconsecutive vertices of a polygonFor a convex polygon with n sides:The sum of the interior angles isThe measure of one interior angle isThe sum of the exterior angles isThe measure of one exterior angle is
7Examples….. Sum of the measures of the interior angles of a 11-gon is The measure of an exterior angle of a regular octagon isThe number of sides of regular polygon with exterior angle 72 ° isThe measure of an interior angle of a regular polygon with 30 sides