Name the polygons with the following number of sides: Triangle Quadrilateral Pentagon Hexagon Heptagon Octagon Nonagon Decagon Dodecagon
Polygons Geometry Mr. Zampetti Unit 3, Day 2
Today’s Objectives To learn how to classify polygons To learn how to find the sum of the measures of the interior and exterior angles of a polygon
Definition Polygon: a closed plane figure with at least three sides.
Video: Polygons in Architecture
Without the use of your notes: Matching names with number of sides: _rand= _rand= Concentration game:
Definition Convex: a polygon is convex if no diagonal contains points outside the polygon.
Definition Concave: a polygon is concave if a diagonal contains points outside the polygon.
Theorem 2-3: Polygon Interior Angle-Sum Theorem The sum of the measures of the interior angles of an n-gon is (n - 2)180.
Practice Find the sum of the measure of the interior angle of the following polygons: –15-gon –20-gon –Decagon –Dodecagon
(n-2) x 180 video Cool Video!!
Theorem 2-4: Polygon Exterior Angle-Sum Theorem The sum of the measures of the exterior angles of a polygon, one at each vertex, is
Video: General Definitions of Polygons
Definition Equilateral polygon: a polygon with all sides congruent. Equiangular polygon: a polygon with all angles congruent. Regular polygon: a polygon that is both equilateral and equiangular.
Homework Work Packet: Polygons