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Think About a Plan The Davis family is planning to drive from San Antonio to Houston. About how far will they have to drive?
- How can you find the distance between the two cities on the map?
- What proportion can you set up to solve the problem?
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Reasoning Two polygons have corresponding side lengths that are proportional. Can you conclude that the polygons are similar? Justify your reasoning.
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Writing Explain why two congruent figures must also be similar. Include scale factor in your explanation.
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J
L
K
white up pointing triangle j l k and
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R
T
S
white up pointing triangle r t s are similar. The scale factor of
△
J
L
K
white up pointing triangle j l k to
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R
T
S
white up pointing triangle r t s is 3 : 1. What is the scale factor of
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R
T
S
white up pointing triangle r t s to
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J
L
K
?
white up pointing triangle j l k question mark
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Open-Ended Draw and label two different similar quadrilaterals. Write a similarity statement for each and give the scale factor.
Algebra Find the value of x. Give the scale factor of the polygons.
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W
L
J
∼
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Q
B
V
white up pointing triangle w l j , tilde operator white up pointing triangle q b v
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G
K
N
M
∼
V
R
P
T
g k n m tilde operator v r p t
Sports Choose a scale and make a scale drawing of each rectangular playing surface.
- A soccer field is 110 yd by 60 yd.
- A volleyball court is 60 ft by 30 ft.
- A tennis court is 78 ft by 36 ft.
- A football field is 360 ft by 160 ft.
Determine whether each statement is always, sometimes, or never true.
- Any two regular pentagons are similar.
- A hexagon and a triangle are similar.
- A square and a rhombus are similar.
- Two similar rectangles are congruent.
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Architecture The scale drawing below is part of a floor plan for a home. The scale is
1
cm
=
10
ft
.
1 , cm , equals 10 , ft , . What are the actual dimensions of the family room?
C Challenge
- The lengths of the sides of a triangle are in the extended ratio 2 : 3 : 4. The perimeter of the triangle is 54 in.
- The length of the shortest side of a similar triangle is 16 in. What are the lengths of the other two sides of this triangle?
- Compare the ratio of the perimeters of the two triangles to their scale factor. What do you notice?