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