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Explore the angles and properties of polygons, including regular polygons, interior angle sum theorem, and exterior angle sum theorem.
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Section 3-5 Angles of a Polygon
Polygon • Means: “many-angled” • A polygon is a closed figure formed by a finite number of coplanar segments a. Each side intersects exactly two other sides, one at each endpoint. b. No two segments with a common endpoint are collinear
Two Types of Polygons: • Convex: If a line was extended from the sides of a polygon, it will NOT go through the interior of the polygon.
2. Nonconvex: If a line was extended from the sides of a polygon, it WILL go through the interior of the polygon.
Polygons are classified according to the number of sides they have. *Must have at least 3 sides to form a polygon. Special names for Polygons *n stands for number of sides.
Diagonal • A segment joining two nonconsecutive vertices *The diagonals are indicated with dashed lines.
Definition of Regular Polygon: • a convex polygon with all sides congruent and all angles congruent.
Interior Angle Sum Theorem • The sum of the measures of the interior angles of a convex polygon with n sides is
One can find the measure of each interior angle of a regular polygon: • Find the Sum of the interior angles • Divide the sum by the number of sides the regular polygon has.
One can find the number of sides a polygon has if given the measure of an interior angle
Exterior Angle Sum Theorem • The sum of the measures of the exterior angles of any convex polygon, one angle at each vertex, is 360.
One can find the measure of each exterior angle of a regular polygon: One can find the number of sides a polygon has if given the measure of an exterior angle