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3 4 5 6 7 8 9 10 12. Triangle Quadrilateral Pentagon Hexagon Heptagon Octagon Nonagon Decagon Dodecagon. Name the polygons with the following number of sides:. Polygons. Geometry Mrs. King Unit 3, Lesson 4. Definition.
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3 4 5 6 7 8 9 10 12 Triangle Quadrilateral Pentagon Hexagon Heptagon Octagon Nonagon Decagon Dodecagon Name the polygons with the following number of sides:
Polygons Geometry Mrs. King Unit 3, Lesson 4
Definition Polygon: a closed plane figure with at least three sides.
Its vertices are A, B, C, D, and E. Its sides are AB, BC, CD, DE, and EA. Its angles are named by the vertices, A, B, C, D, and E. Name the polygon. Then identify its vertices, sides, and angles. Possible names are ABCDE and EDCBA.
Without the use of your notes: Matching names with number of sides: http://www.quia.com/cm/86645.html?AP_rand=2098901149 Concentration game: http://www.quia.com/jg/1507267.html
Definition Convex: a polygon is convex if no diagonal contains points outside the polygon. http://img.sparknotes.com/figures/B/b333d91dce2882b2db48b8ad670cd15a/convexconcave.gif
Definition Concave: a polygon is concave if a diagonal contains points outside the polygon. http://img.sparknotes.com/figures/B/b333d91dce2882b2db48b8ad670cd15a/convexconcave.gif
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.
Find the sum of the measures of the angles of a decagon. A decagon has 10 sides, so n = 10. Sum = (n – 2)(180) = (10 – 2)(180) = 8 • 180 = 1440
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!!
Find m X in quadrilateral XYZW. The figure has 4 sides, so n = 4.
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 360. http://www.mathlove.com/new3/product/img/TTA05/5.jpg
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.