COURSE 3 LESSON 5-7
Scale Models and Maps
On a blueprint, the living room is 4 in. by 3 in. The scale is
1 in. = 8 ft. What are the length and width of the actual living room?
2
First, find the actual length of the living room.
Let
= the actual length of the living room.
blueprint measure (in.)
actual measure (ft)
1
2
4
=
8
blueprint length (in.)
actual length (ft)
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COURSE 3 LESSON 5-7
Scale Models and Maps
(continued)
1
•
2
1
2
1
2
1
2
=8•4
Write the cross
products.
= 32
Simplify.
=
32
1
2
= 64
Divide each side
1
by .
2
Simplify.
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COURSE 3 LESSON 5-7
Scale Models and Maps
(continued)
The length of the actual room is 64 ft.
Next, find the actual width of the living room.
Let w = the actual width of the living room.
blueprint measure (in.)
actual measure (ft)
1
2
3
=
8
w
blueprint length (in.)
actual length (ft)
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COURSE 3 LESSON 5-7
Scale Models and Maps
(continued)
1
• w=8•3
2
Write the cross
products.
1
w = 24
2
Simplify.
1w
24
2
=
1
1
2
2
Divide each side
1
by .
w = 48
2
Simplify.
The width of the actual room is 48 ft.
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COURSE 3 LESSON 5-7
Scale Models and Maps
The map distance from El Paso, Texas, to Chihuahua,
Mexico, measures about 7.5 cm. The scale is 1 cm = 50 km. Find the
actual distance using a proportion.
Let x = the actual distance.
map (cm)
actual measure (km)
1 • x = 50 • 7.5
x = 375
1
7.5
= x
50
map (cm)
actual (km)
Write the cross products.
Simplify.
The distance from El Paso to Chihuahua is 375 km.
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COURSE 3 LESSON 5-7
Scale Models and Maps
1. A 6-ft man is designing a new chair that would make him feel like a 2.5-ft
child. The seat of a normal chair is 1.5 ft high. How high should he make
the seat in his new chair?
3.6 ft
2. A map scale shows 4 cm to represent 6 km. Two intersections measure
1 cm apart on the map. What is the actual distance?
1.5 km
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