Chp. 5.7 ­ Diagonals and Angles of Polygons
March 05, 2013
Date:
Chapter: Chapter 5:7 ­­> Diagonals and Angles of Polygons
Objectives: Classify polygons
Find the sum of the angle measures
Integrated Math II
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Chp. 5.7 ­ Diagonals and Angles of Polygons
March 05, 2013
Notes:
*Polygon = Simple, closed plane figure formed by joining three or more line segments at their endpoints.
*Side = Segment of polygon that intersects exactly two other segments.
*Vertex = Point at which the endpoints meet.
­­­Polygons are named by their sides!!­­­
Triangle = 3 sides
Quadrilateral = 4 sides
Pentagon = 5 sides
Hexagon = 6 sides
Heptagon = 7 sides
Octagon = 8 sides
Nonagon = 9 sides
Decagon = 10 sides
Dodecagon = 12 sides
*any other polygon = n­gon
*Convex = Each line containing a side has no points in the interior of the polygon.
*Concave = The line that contains a side also contains a point in the interior of the polygon.
*Regular = A polygon that has all sides and angles congruent.
Figure # Sides
# Triangles
Sum of <s
Sum of Interior <s
(n ­ 2)180 where n = # sides
Each interior <
In a regular polygon.....where n = # of sides
m< = (n ­ 2)180
n
Integrated Math II
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Chp. 5.7 ­ Diagonals and Angles of Polygons
March 05, 2013
Examples:
Ex. 1 ­ Classify each polygon then state convex or concave, regular or not regular.
a)
b)
c)
d)
Ex. 2 ­ Find the sum of the interior <s
a) pentagon
b) heptagon
Ex. 3 A beehive is a large array of regular hexagons. Find the measure of each interior < of the regular hexagon.
Integrated Math II
3
Chp. 5.7 ­ Diagonals and Angles of Polygons
March 05, 2013
Homework:
p. 224 (#1­3, 15­30)
Integrated Math II
4