ON
L E SS
Name
Date
8.6 Study Guide
For use with pages 399–403
G OAL
Use proportions with scale drawings.
VOCABULARY
Lesson 8.6
A scale drawing is a diagram of an object in which the
dimensions are in proportion to the actual dimensions of the
object.
The scale on a scale drawing tells how the drawing’s
dimensions and the actual dimensions are related.
A scale model is a model of an object in which the dimensions
are in proportion to the actual dimensions of the object.
E X A M P LE
1 Using the Scale of a Map
Use the map of Florida to estimate the distance between the cities of
Tallahassee and Miami.
Solution
From the map’s scale, 1 centimeter
represents 120 kilometers. On the
map, the distance between Tallahassee
and Miami is 5.5 centimeters.
Tallahassee
Jacksonville
Orlando
Write and solve a proportion to find
the distance d between the cities.
1
5.5
ᎏᎏ ⫽ ᎏᎏ
120
d
centimeters
kilometers
1 p d ⫽ 120 p 5.5
d ⫽ 660
Miami
Florida
1 cm : 120 km
Answer: The actual distance between Tallahassee and Miami is about
660 kilometers.
Exercises for Example 1
Use a metric ruler and the map in Example 1.
1. Estimate the distance, in kilometers, between the cities of
Tallahassee and Orlando.
2. Estimate the distance, in kilometers, between the cities of
Jacksonville and Miami.
58
Middle School Math, Course 2
Chapter 8 Resource Book
Copyright © McDougal Littell Inc.
All rights reserved.
L E SS
ON
Name
Date
8.6 Study Guide
Continued
For use with pages 399–403
E X A M P LE
2 Finding a Dimension on a Scale Model
A scale drawing of Seattle’s Space Needle uses a scale of 1 in. : 55 ft.
The actual height of the Space Needle is 605 feet. Find the height in
the drawing.
Solution
1
h
ᎏᎏ ⫽ ᎏᎏ
55
605
Lesson 8.6
Write and solve a proportion to find the height h of the Space Needle in
the drawing.
scale drawing
Seattle Space Needle
1 p 605 ⫽ 55 p h
Cross products property
11 ⫽ h
Divide each side by 55.
Answer: The height of the Space Needle in the drawing is 11 inches.
E X A M P LE
3 Finding the Scale
Kirk is putting together a model car from a kit. The model car has a
length of 14 inches. The actual car has a length of 16 ᎏ13ᎏ feet. What is
the model’s scale?
Solution
Write a ratio. Make sure both measures are in inches. Then simplify
the fraction.
14 in.
14 in.
1
ᎏ
⫽ ᎏ ᎏ ⫽ ᎏᎏ
196 in.
14
16 ᎏ13ᎏ ft
Answer: The model’s scale is 1 : 14.
Exercise for Examples 2 and 3
3. On Mount Rushmore, the distance from George Washington’s
forehead to his chin is 60 feet. The distance from forehead to
chin on an average human is 9 inches. Find the scale of the face
of an average human to the face of George Washington on
Mount Rushmore.
Copyright © McDougal Littell Inc.
All rights reserved.
Middle School Math, Course 2
Chapter 8 Resource Book
59