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GEOMETRY: Chapter 11. 11.1: Angle Measures in Polygons. The sum of the measures of the interior angles of a convex n -gon is ( n – 2)(180 o ). Theorem 11.1 : Polygon Interior Angles Theorem. Image taken from: Geometry. McDougal Littell: Boston, 2007. P. 507.
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GEOMETRY: Chapter 11 11.1: Angle Measures in Polygons
The sum of the measures of the interior angles of a convex n-gon is (n – 2)(180o). Theorem 11.1:Polygon Interior Angles Theorem Image taken from: Geometry. McDougal Littell: Boston, 2007. P. 507.
Corollary to Theorem 11.1: Interior Angles of a Quadrilateral The sum of the measures of the interior angles of a quadrilateral is 360o.
Ex.1: Find the sum of the measures of the interior angles of a convex decagon. Answer: 1440 degrees
Ex. 2: The sum of the measures of the interior angles of a convex polygon is 2340o. Classify the polygon by the number of sides. Answer: 15-gon
Ex. 3: Find the value of x in the diagram shown. Answer: 154 Images taken from: Geometry. McDougal Littell: Boston, 2007. P.508.
Exterior Angles—Unlike the sum of the interior angle measures of a convex polygon, the sum of the exterior angle measures does NOT depend on the number of sides of a polygon.
Theorem 11.2: Polygon Exterior Angles Theorem The sum of the measures of the exterior angles of a convex polygon, one angle at each vertex, is 360o. Image taken from: Geometry. McDougal Littell: Boston, 2007. P. 509.
Ex. 4: What is the value of x in the diagram shown? Answer: 66 Image taken from: Geometry. McDougal Littell: Boston, 2007. P. 509.
Ex. 5: A stop sign is shaped like a regular octagon. Find (a) the measure of each interior angle and (b) the measure of each exterior angle. Answer: a) 135 degrees; b) 45 degrees