Transcript Maps and Scale Drawings

COURSE 2 LESSON 5-7
Maps and Scale Drawings
(For help, go to Lesson 5-4.)
Solve each proportion.
1. 2 = x
3
12
2. 9 = 27
5
y
3. 15 = 25
m
5
4. 3 = c
5
30
5. t = 6
21
18
6. 13 = 52
n
4
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COURSE 2 LESSON 5-7
Maps and Scale Drawings
Solutions
1. 3x = 24; x = 24 = 8
3
3. 25m = 75; m =
75
=3
25
126
5. 18t = 126; t = 18 = 7
2. 9y = 135; y = 135 = 15
9
4. 5c = 90; c =
90
= 18
5
52
6. 52n = 52; n = 52 = 1
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COURSE 2 LESSON 5-7
Maps and Scale Drawings
Find three integers whose sum is 12 and whose product is 42.
2, 3, 7
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COURSE 2 LESSON 5-7
Maps and Scale Drawings
The scale of a drawing is 1 in. : 6 ft. Find the actual
length for a drawing length of 4.5 in.
Write the scale of the drawing, 1 in. = 6 ft, as 1 in. . Then write a proportion in
6 ft
which each ratio compares inches to feet.
Let n represent the actual length.
drawing (in.)
actual (ft)
drawing (in.)
actual (ft)
1
4.5
=
6
n
1n = 6(4.5)
n = 27
Write cross products.
Simplify.
The actual length is 27 ft.
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COURSE 2 LESSON 5-7
Maps and Scale Drawings
On a map of North Carolina, the map distance from Asheville
to Raleigh would be about 4.4 cm. Find the actual distance from
Asheville to Raleigh. The scale on the map is 1 cm : 75 km .
map (cm)
actual (km)
map (cm)
actual (km)
1
4.4
=
75
n
1n = 75(4.4)
Write a proportion.
Write cross products.
n = 330
Simplify.
The actual distance from Asheville to Raleigh is about 330 km.
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COURSE 2 LESSON 5-7
Maps and Scale Drawings
The actual length of the wheelbase of a mountain bike is
260 cm. The length of the wheelbase in a scale drawing is 4 cm. Find
the scale of the drawing.
scale length
actual length
4
1
=
260
65
Divide each measure by the GCF, 4.
The scale is 1 cm : 65 cm.
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COURSE 2 LESSON 5-7
Maps and Scale Drawings
1. The scale of a map is 1 cm : 25 km. Find the actual distance for a map
distance of 6.2 cm.
155 km
2. The actual length of a machine part is 40 in. The length of the machine
part in a scale drawing is 5 in. Find the scale of the drawing.
1 in. : 8 in.
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