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Angles of Polygons. Let's Discuss. What does the word “polygon” mean?. What is the smallest number of sides a polygon can have?. What is the largest number of sides a polygon can have?. Triangle. Octagon. Quadrilateral. Nonagon. Pentagon. Decagon. Dodecagon. Hexagon. n-gon. Heptagon.
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Let's Discuss What does the word “polygon” mean? What is the smallest number of sides a polygon can have? What is the largest number of sides a polygon can have?
Triangle Octagon Quadrilateral Nonagon Pentagon Decagon Dodecagon Hexagon n-gon Heptagon Hendecagon
Hip Bone’s connected to the…Classifying Polygons Polygons with 3 sides… Triangles Polygons with 4 sides… Quadrilaterals Polygons with 5 sides.. Pentagons But wait we have more polygons Polygons with 6 sides… Hexagons Polygons with 7 sides… Heptagons Polygons with 8 sides… Octagons But still we have more polygons Polygons with 9 sides… Nonagons Polygons with 10 sides… Decagons Polygons with 12 sides… Dodecagons And now we have our polygons
A VERTEX is the point of intersection of two sides CONSECUTIVE VERTICESare two endpoints of any side. A B F C A segment whose endpoints are two nonconsecutive vertices is called a DIAGONAL. E D Sides that share a vertex are called CONSECUTIVE SIDES. Important Terms
Polygons are named by listing its vertices consecutively. A B C F E D
More Important Terms EQUILATERAL - All sides are congruent EQUIANGULAR - All angles are congruent REGULAR- All sides and angles are congruent
Interior Angles Exterior Angles Three more important terms SUPPLEMENTARY the SUM of an interior angle and it’s corresponding exterior angle = 180o
Polygons can be CONCAVE or CONVEX CONCAVE CONVEX
Classify each polygon as convex or concave. Concave Concave Concave CONVEX
It’s what’s inside that counts Finding and using the interior angle measures of polygons
What is the sum of the measures of the interior angles of a triangle? 180° 180° 180° What is the sum of the measures of the interior angles of any quadrilateral? 360°
Sum of measures of interior angles # of triangles # of sides 1(180) = 180 3 1 2(180) = 360 4 2 3 3(180) = 540 5 6 4 4(180) = 720 n-2 (n-2) 180 n
If a convex polygon has n sides, then the sum of the measure of the interior angles is (n – 2)(180°)
If you know the sum of the angles of a regular polygon, how can you find the measure of one of the congruent angles?
If a regular convex polygon has n sides, then the measure of one of the interior angles is
HOMEWORK pg 300 1-15