Geometry Section: 8.1 Classifying Polygons
Algebra Problem of the Day: Write an equation of a line in slope intercept form with a slope of ­2/3 through the point (3, ­6).
Nov 7­9:00 AM
Today's Essential Question: How can I describe polygons?
Opener: Graphic Organizer of today's lesson
Polygons can be described in two categories:
POLYGONS
EQUIANGULAR OR
EQUILATERAL
OR
REGULAR
CONVEX OR CONCAVE
Feb 27­3:40 PM
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Concept 1: Identifying Convex and Concave Polygons Convex Polygon: A polygon is convex if no line that contains a side of the polygon passes through the interior of the polygon.
Concave Polygon: A polygon that is not convex.
(Caves in)
Feb 27­3:47 PM
Concept 2: Equilateral, Equiangular and Regular Polygons
A Polygon is Equilateral when all of its sides are congruent.
+ A Polygon is Equiangular if all of its interior angles are congruent.
A Polygon is Regular if it is both Equilateral and Equiangular
Equilateral Equiangular
Regular Feb 27­8:47 PM
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Decide whether the polygon is Concave or Convex. Then decide whether the polygon is Equilateral, Equiangular, or Regular. Explain your answer.
Ex. 1:
Ex. 2:
Ex. 3:
Feb 27­8:58 PM
Closure: Finding Perimeters
The following polygons are equilateral. Ex. 1: Find the perimeter of this polygon.
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Ex. 2: Find the measure of one side of the polygon given that the perimeter is 30.
The following polygons are regular. Find the value of x.
Ex. 3: Ex. 4:
52
x + 10
4x
Feb 27­9:06 PM
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Learning Opportunity:
p. 413­415 #1­21, 27­38, 44­51
Feb 27­9:16 PM
Mar 2­12:44 PM
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Mar 2­12:44 PM
Mar 2­12:44 PM
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