SIMILARITY:

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SIMILARITY A REVIEW
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Midsegment a segment that joins the midpoints of
2 sides of a triangle?
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A Midsegment is parallel to one side of the
triangle and half of its length.
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Find x, the length of the midsegment
x
16
X 8
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midsegments
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Find x, y, z
z
8
y
7
x
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midsegments
20
x8, y10, z14
z
8
y
7
x
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Property of Proportions 1
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Property of Proportions 2
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Property of Proportions 3
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Property of Proportions 4
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Property of Proportions 5
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PRACTICE
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Definition Polygons are similar if
1. Corresponding Angles are congruent 2.
Corresponding sides are in proportion
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7.5
Find w, x, y, z in these similar trapezoids
8
y
x
z
10
12
w
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7.5
8
y
x
z
10
12
w
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7.5
W60o
8
X9.375
y
x
Y9.6
z
10
Z120o
12
w
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Similar Triangles
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AA Postulate If 2 angles of one triangle are
congruent to 2 angles of another triangle, then
the 2 triangles are similar.
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SSS Postulate If all 3 sides of two triangles
are in proportion, then the triangles are similar.
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SAS Postulate If 2 sides of two triangles are
in proportion and their included angles are
congruent, the triangles are similar.
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PRACTICE
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Similar?
4
Yes by SAS
7
10
17.5
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Similar?
5
Yes by SSS
6
8
8.4
7
11.2
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Similar?
Yes by AA
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Similar?
68o
No! Corresponding angles are not
congruent .
50o
62o
48o
70o
62o
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Find x
8
7
4
x
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Find x
x
6
4
9
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