Download Polygons

polygons.notebook
February 20, 2011
Polygons
Learning Target: I am learning to identify and define the different types of polygons.
•
I am learning to determine the measures of the interior and exterior angles of polygons.
Essential Questions: How do you determine the sum of the
measures of the interior angles of any polygon?
How do you determine the sum of the
measures of the exterior angles of any polygon?
Jan 15­6:53 PM
The tiles that protect the space shuttle during reentry are designed, fabricated, assembled by technicians using the properties of polygons and quadrilaterals.
Jan 15­7:00 PM
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polygons.notebook
February 20, 2011
Triangles, squares, rectangles, hexagons, and octagons are a few of the many types of polygons found in the world around you. You have already seen that triangles are used to construct ridged structures such as the Statue of Liberty and bridges. Squares and rectangles are important because of their 90o angles. Many tile floors are designed with hexagons and or quadrilaterals. Street signs are polygons such as, stop signs which are octagonal. Jan 15­7:03 PM
Figures A, C, E, F, I and L are polygons.
So what makes something a polygon?
A polygon is a plane shape (two dimensional) bounded by 3 or more straight line segments. It is a closed figure. The line segments only intersect two other segments at their endpoints.
Jan 15­7:19 PM
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polygons.notebook
February 20, 2011
Two types of Polygons: 1. Convex
2. Concave
A
B
lens
lens
Any points of a segment joining two points in the interior of a polygon must also be in the interior of the polygon.
Jan 15­7:28 PM
Polygons are classified by number of sides:
Number Name
of Sides
Number of Sides
Name
3
Triangle
9
Nonagon
4
Quadrilateral 10
Decagon
5
Pentagon 11
Undecagon or Hendecagon
6
Hexagon
12
Dodecagon
7
Heptagon
n
n­gon
8
Octagon
Just A Boring Square
Jan 15­7:46 PM
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polygons.notebook
February 20, 2011
In an equilateral polygon, all sides are congruent. In an equiangular polygon, all interior angles are congruent. These properties lead to the definition of a regular polygon.
A Regular Polygon: A polygon is regular if it is both equilateral and equiangular.
Jan 15­8:02 PM
1. Is a rectangle a regular polygon?
2. Name a regular quadrilateral?
3. Are there any triangles that are regular polygons?
4. Are these shapes polygons?
a.
b.
Jan 15­8:29 PM
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