7.4 Similarity in Right Triangles 2011
January 19, 2011
7.4 Similarity in Right Triangles
Objective: Find and use relationships in similar right triangles.
Feb 11­7:46 AM
1
7.4 Similarity in Right Triangles 2011
January 19, 2011
Warmup
Name the three right triangles in the figure below.
C
A
D
B
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7.4 Similarity in Right Triangles 2011
January 19, 2011
Similarity in Right Triangles
C
B
D
A
D
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3
7.4 Similarity in Right Triangles 2011
January 19, 2011
Appropriately label each side of the three similar triangles. Then give the similarity statement. C
b
B
A
a
h
r
s
B
D
c
B
C
C
A
D
C
A
D
Feb 11­8:54 AM
4
7.4 Similarity in Right Triangles 2011
January 19, 2011
Write the proportionality statements for each set of similar triangles.
a
b
h
r
s
c
a
a
r
b
b
h
h
s
Short leg & Hypotenuse Long leg & Hypotenuse Long leg & Short leg
Large to Medium
Large to Small
Medium to Small
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7.4 Similarity in Right Triangles 2011
January 19, 2011
Example #1
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7.4 Similarity in Right Triangles 2011
January 19, 2011
Example #2
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7.4 Similarity in Right Triangles 2011
January 19, 2011
Example #3
a. A service station will be built on the highway, and a road will connect it with Cray. How far from Blare should the service station be located so that the proposed road will be perpendicular to the highway?
b. How long will the new road be?
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7.4 Similarity in Right Triangles 2011
January 19, 2011
New Vocabulary: Geometric Mean
a
x
The geometric mean of a and b is the positive number x such that . x = b
Find the geometric mean of:
4 and 9:
3 and 18:
5 and 9:
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7.4 Similarity in Right Triangles 2011
January 19, 2011
Homework
p. 394
# 1 ­ 7 odd, 9 ­ 20, 22, 34 ­ 36
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