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In this section we will…
CLASSIFY POLYGONS
Ch 1.6
Look at what makes something a polygon.
Identify polygons by their sides and angles
Identify polygons by concave and convex
Apply algebraic problems to the geometric facts
What is a polygon?
A polygon is a shape with at least 3 straight closed
sides that do not cross over each other.
Remember these?
Sides of a polygon are the straight lines that create
the polygon.
The vertices of a polygon are where the sides
meet.
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Convex VS Concave
Convex polygons are polygons where all the
vertices point outward.
Concave polygons are polygons where at least
one vertex points inward.
Are you equilateral, equiangular, regular, or
none?
What is it?
Equilateral polygons have sides that are all of the
same length. (All sides are of equal length)
Equiangular polygons have angles that are all if
the same angle measure. (All angles are the same
measure)
Regular polygons are both equilateral and
equiangular.
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Page 44
#3 - 14
Let’s apply some algebra
7x + 34 = 11x – 14
48 = 4x
12 = x
7(12) + 34 = 118
Assuming that the polygon is regular, find x.
5x + 13 = 10x – 7
20 = 5x
4=x
5(4) + 13 = 33
X2 – x + 55 = X2 + 4x + 5
-x + 55 = 4x + 5
50 = 5x
10 = x
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Assuming that the polygon is regular, find x.
Page 45 # 15 – 17, 28 - 30
X2 + 12x - 106 = X2 - 6x – 16
12x - 106 = -6x - 16
18x = 90
x=5
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