6.1 polygons textbook page 303. definitions a polygon is a plane figure that is formed by three or...
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6.1 Polygons
Textbook page 303
Definitions A polygon is a plane figure that is
formed by three or more segments called sides. (a closed, sided figure)
Each side intersects exactly two other sides at each of its endpoints. Each endpoint is a vertex of the polygon.
Two vertices that are endpoints of the same side are consecutive vertices.
A segment that joins two nonconsecutive vertices of a polygon is called a diagonal.
Verticesside
diagonal
Consecutive vertices
Is the figure a polygon? Why or why not?
Yes, the figure is closed and formed by straight sides
Is the figure a polygon? Why or why not?
No, one of the “sides” is not a segment – it is a curve
Is the figure a polygon? Why or why not?
No, two of the sides only intersect one other side – it is not a closed figure
Is the figure a polygon? Why or why not?
Yes, the figure is closed and formed by straight sides
Naming Polygons
Number of Sides Name of Polygon
3
4
5
6
7
8
9
10
12
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4
5
6
7
8
9
10
12
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4 Quadrilateral
5
6
7
8
9
10
12
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4 Quadrilateral
5 Pentagon
6
7
8
9
10
12
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4 Quadrilateral
5 Pentagon
6 Hexagon
7
8
9
10
12
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4 Quadrilateral
5 Pentagon
6 Hexagon
7 Heptagon or Hectagon
8
9
10
12
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4 Quadrilateral
5 Pentagon
6 Hexagon
7 Heptagon or Hectagon
8 Octagon
9
10
12
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4 Quadrilateral
5 Pentagon
6 Hexagon
7 Heptagon or Hectagon
8 Octagon
9 Nonagon
10
12
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4 Quadrilateral
5 Pentagon
6 Hexagon
7 Heptagon or Hectagon
8 Octagon
9 Nonagon
10 Decagon
12
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4 Quadrilateral
5 Pentagon
6 Hexagon
7 Heptagon or Hectagon
8 Octagon
9 Nonagon
10 Decagon
12 Dodecagon
n
Naming Polygons
Number of Sides Name of Polygon
3 Triangle
4 Quadrilateral
5 Pentagon
6 Hexagon
7 Heptagon or Hectagon
8 Octagon
9 Nonagon
10 Decagon
12 Dodecagon
n n-gon
Quadrilaterals
Quadrilaterals are made of two triangles. The sum of the angles in a triangle is 180o. 2 * 180 = 360
total 180o
total 180o
Quadrilateral Interior Angles Theorem
The sum of the interior angles of a quadrilateral is 360o.
m<1 + m<2 + m<3 + m<4 = 360o
4
1
3
2
Find the measure of <A
900
A
B
C
D
1100
600
1000
Find the measure of <A
650
AB
C
D
550
800
1600
Find the measure of <A
720
A
B
C
D
1080
720
1080
Homework
Assignment # 10 Textbook page 306 Problems 1-23, 30-42 You do not have to write the problems, but
you MUST show your work on 6,7, 15-20, and 37-42