1. Insert Lesson Title Here
Course 2
Scale Drawings and Scale Models
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Vocabulary
scale model
scale factor
scale drawing

2. Scale Models and Scale Drawings
Course 2
Scale Models and Scale Drawings
A scale model is a proportional model of a three-dimensional object..

3. Scale Models and Scale Drawings
Course 2
Scale Models and Scale Drawings
A scale drawing is a proportional drawing of an object.
Its dimensions are related to the dimensions of the actual object by a ratio called the scale factor.

4. Scale Models and Scale Drawings
Course 2
Scale Models and Scale Drawings
A scale factor is always the ratio of the model’s dimensions to the actual object’s dimensions.
Caution!
Model
Actual

5. Example 1: Identify the Scale Factor
Scale Drawings and Scale Models
Example 1: Identify the Scale Factor
Room
Blueprint
Length (in.)
144 18
Width (in.)
108
13.5
blueprint length
room length 18
144
Write a ratio using one of the
dimensions. = 1 8 =
Simplify. 1 8
The scale factor is .

6. Insert Lesson Title Here
Course 2
Scale Drawings and Scale Models
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Example 2
Identify the scale factor.
Model Aircraft
Blueprint
Length (in.) 12 2
Wing span (in.) 18 3
blueprint length
aircraft length 2 12 =
Write a ratio using one of the dimensions. 1 6 =
Simplify.
The scale factor is . This is reasonable because of the length of the model is 3 in. The length of the blueprint is 2, which is less. is less than . 1 6 4

7. Insert Lesson Title Here
Course 2
Scale Drawings and Scale Models
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Example 3
On a road map, the distance between Dallas and Houston is 7 inches. What is the actual distance between the cities if the map scale is 1 inch = 50 kilometers?
Let d be the actual distance between the cities. 1 50 7 d =
Write a proportion.
1 · d = 50 · 7
Find the cross products.
1d = 350
Multiply.
d = 350
The distance between the cities is 350 kilometers.

8. Scale Drawings and Scale Models
Course 2
Scale Drawings and Scale Models
Example 4
On a road map, the distance between Pittsburgh and Philadelphia is 7.5 inches. What is the actual distance between the cities if the map scale is 1.5 inches = 60 miles?
Let d be the actual distance between the cities.
1.5 60
7.5 d =
Write a proportion.
1.5 · d = 60 · 7.5
Find the cross products.
1.5d = 450
Multiply.
1.5d
1.5
450
1.5 =
Divide both sides by 1.5.
d = 300
The distance between the cities is 300 miles.

9. Scale Drawings and Scale Models
Course 2
Scale Drawings and Scale Models
Example 5:
On a scale drawing, a school is 1.6 feet tall.
The scale factor is Find the height of the school. 1 22
1.6 h 1 22
Think: =
1.6 h 1 22 =
Write a proportion to find the height.
1h = 35.2
Find the cross products.
h = 35.2 feet
Divide.

10. Scale Drawings and Scale Models Insert Lesson Title Here
Course 2
Scale Drawings and Scale Models
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Lesson Quiz: Part I
Identify the scale factor. 1.
Statue of Liberty
Model
Height (in.)
1,824 8 1
228 2.
On a scale drawing, a kitchen wall is 6 inches long.
The scale factor is What is the length of the
actual wall? 1 24
144 inches, or 12 feet

11. Scale Drawings and Scale Models Insert Lesson Title Here
Course 2
Scale Drawings and Scale Models
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Lesson Quiz: Part II 3.
A countertop is 18 ft long. How long is it on a scale drawing with the scale 1 in. = 3 yd?
2 in