Download similarity 26

Similarity
Lesson 26
Question of the Day:
Dilate triangle ABC about the origin by a scale factor of 2 to create triangle DEF. Graph the
image and label the vertices DEF.
Class Discussion:
1.) Are the two triangles similar? Why?
2.) What is the ratio of the corresponding sides?
3.) Proportional sides (corresponding sides):
4.) State the corresponding (congruent) angles.
5.) Write a similarity statement: ___________________________.
Similar Figures: Figures that have the _________ _________ but are a ____________ ________.
One is a _____________ of the other
Angles are _________________
Sides are ___________________
Similarity ratio: The ___________between the ______________ __________of similar
figures
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Examples:
1.) State if the two triangles are similar.
If so, write a similarity statement:
P
4
1.4
K
2.) Find the similarity ratio. Then, state the
corresponding angles and proportional sides.
S
M
5
2
2.8
3.5
L
U
To find the similarity ratio:
To show two triangles are similar:
To write a similarity statement:
3.) Find the scale factor of
SAT to
SEA if:
SAT ~
SEA, EA = 6, ST = 24, and AT = 18
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Independent practice
Lesson 26
For #1-2, determine the scale factor for the triangles. Write a similarity statement and state the
proportional sides:
1.)
2.)
A
B
9
3
5
15
E
6
2
C
D
For # 3-4, state if the triangles are similar.
3.)
4.) ΔMNO has sides of lengths 4, 5, and 6.
ΔRST has sides of lengths 8, 9, and 10.
5.) State the congruent angles and proportional sides. ∆𝑆𝐺𝑅 ~ ∆𝑄𝑊𝑅
6.) Dilate the figure below by a scale factor of -2 centered at the point (2, -3)
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