Exploring Polygons By the end of class you will be able to: Identify Convex and Concave Polygons...
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Transcript of Exploring Polygons By the end of class you will be able to: Identify Convex and Concave Polygons...
Exploring Polygons
By the end of class you will be able to:
• Identify Convex and Concave Polygons
•Name Parts of a Polygon
•Classify Polygons
Convex or Concave?A Polygon is a plane figure formed by three or more segments.A Polygon can either be convex or concave.
If a polygon is convex then no sides go through the interior of the polygon.
(All vertices point outside the polygon.)
If a polygon is concave then it is not convex. A side goes through the interior of the polygon.
(At least one vertex points inside the polygon.)
Example 1:
Which figures are polygons?
Example 2:
Label the polygons as convex or concave?
Example 1:
Which figures are polygons?
polygon polygon polygon
polygon
Example 2:
Label the polygons as convex or concave?
convex concave concave convex
Parts of a polygonThe simplest polygon is a triangle. Many of the terms you learned about a triangle apply to all polygons. Remind yourself of what the following terms mean.
Vertices Interior Angles Exterior Angles
Perimeter AreaSides
Parts of a polygonThe simplest polygon is a triangle. Many of the terms you learned about a triangle apply to all polygons. Remind yourself of what the following terms mean.
Vertices
Parts of a polygonThe simplest polygon is a triangle. Many of the terms you learned about a triangle apply to all polygons. Remind yourself of what the following terms mean.
Vertices Interior Angles
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Parts of a polygonThe simplest polygon is a triangle. Many of the terms you learned about a triangle apply to all polygons. Remind yourself of what the following terms mean.
Vertices Interior Angles Exterior Angles
Parts of a polygonThe simplest polygon is a triangle. Many of the terms you learned about a triangle apply to all polygons. Remind yourself of what the following terms mean.
Vertices Interior Angles Exterior Angles
Sides
Parts of a polygonThe simplest polygon is a triangle. Many of the terms you learned about a triangle apply to all polygons. Remind yourself of what the following terms mean.
Vertices Interior Angles Exterior Angles
Perimeter
Add all sides
Sides
Parts of a polygonThe simplest polygon is a triangle. Many of the terms you learned about a triangle apply to all polygons. Remind yourself of what the following terms mean.
Vertices Interior Angles Exterior Angles
Perimeter AreaSides
Parts of a polygonIn more complex polygons there are more parts.
Learn these new terms:
Diagonal RegularConsecutive
Parts of a polygonIn more complex polygons there are more parts.
Learn these new terms:
Refers to parts that are right next to each other.
(They share a common vertex or side.)
Diagonal RegularConsecutive
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Parts of a polygonIn more complex polygons there are more parts.
Learn these new terms:
Diagonal RegularConsecutive
Joins two nonconsecutive vertices.
(Notice the triangle does NOT have any diagonals.)
Parts of a polygonIn more complex polygons there are more parts.
Learn these new terms:
A polygon that is equilateral and equiangular.)
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Diagonal RegularConsecutive
Classifying Polygons
A Polygon is classified by its’ number of sides.
3
4
5
6
7
8
9
10
12
n n - gon
Dodecagon
Decagon
Nonagon
Octagon
Heptagon
Hexagon
Pentagon
Quadrilateral
Triangle
Number of Sides Type of Polygon
Example:
The perimeter of the pentagon is 20. Solve for X.
X+1 2X
2X-1
X + 6
X
Remember what perimeter means
The Sum of all the sides
Example:
The perimeter of the pentagon is 20. Solve for X.
X+1 2X
2X-1
X + 6
X
(X+ 1) + (2X) +(X) + (2x-1) + (x+6 )= 20
Combine like terms and solve
7X + 6 = 207 X = 14
X = 2