Lesson 7.5 Understanding Scale Drawings

Transcription

1 Lesson 7. Understanding Scale Drawings. Richard built a model of a Ferris wheel. The model has a height of 8 inches. The actual Ferris wheel has a height of 23 feet. What scale factor did Richard use for the model? 2. On a blueprint, the height of a door is 3. inches. The actual height of the door is 7 feet. What is the scale on the blueprint? 3. A model of space shuttle Apollo Saturn V is created with a scale of :. If the actual space shuttle has a width of 62. feet, what is the width of the model, in inches?. Timothy has a model of an armoured vehicle created using a scale of : 72. If the length of the model is 3.3 inches, what is the actual length of the vehicle, in feet?. A road map uses a scale of inch : miles. If the distance on the map between two towns is 3.8 inches, what is the actual distance between these two towns? Extra Practice Course 2B 29

2 6. A map shows some cities in the northern part of the United States. The scale of the map is inch : 2 miles. a) The actual distance between Chicago, IL and Pittsburgh, PA is 37 miles. Find the distance between the two cities on the map. b) On the map, the distance between Washington DC and New York City is. inches. Find the actual distance between these two cities. 7. Joan drew a picture of a flower and then made a reduced photocopy of her drawing. The flower in the actual drawing is 6 inches long. The flower in the reduced copy is. inches long. Find the scale factor of the reduction. 8. The Truckee River is about 2 miles in length. What is the length of this river on a map with a scale of inch : 2 miles? 30 Chapter 7 Lesson 7.

3 9. The scale of a map is inch : miles. If the length of Manila Creek Road on this map is 3. inches, find the actual length of the road. 0. Kim is looking at a map with a scale of inch : 8 miles. If the actual area of a farm is 80 square miles, what is the area of the farm on this map?. On a blueprint, the area of a basketball court is 8 square inches. a) If the scale of the blueprint is inch : 9 feet, what is the actual area of the basketball court? b) If the length of the basketball court on the blueprint is 0. inches, what is the actual length of the basketball court? c) What is the actual width of the basketball court to the nearest foot? Extra Practice Course 2B 3

4 P S 7 Q R a) The length of PR is 7.6 cm. The length of QS is 0.2 cm. The segments bisect each other at right angles. b) They are both isosceles triangles. K N 7.2 cm 0 M The length of KN is 6.8 cm. A.8 cm AD 2.7 cm. Lesson 7. B 3 cm 6 cm L cm. foot 2 inches 23 feet ,808 inches 8 in. Scale factor 2, 808 in in. : 7 ft in. : 7 2 ft 3. The scale used for the blueprint is inch : 2 feet. C D 3. cm 3. feet 2 inches 62. feet inches Let x be the width of the model. : Scaled width : Actual width : x : 78.8 x x 78.8 x x.2 The width of the model is.2 inches.. Let x be the actual length of the vehicle. : 72 Scaled width : Actual width : : x ẋ x x in. ft in ft The actual length of the vehicle is 9.8 feet.. Let x be the actual distance in miles. inch : miles 3.8 inches : x miles in. 38. in. mi x mi 38 ẋ x 3.8 x.2 The actual distance between these two towns is.2 miles. 6. a) Map scale Map length : Actual length Let y inches be the length on the map. inch : 2 miles y inches : 37 miles in. in. y 2 mi 37 mi y y 37 2y y 3 On the map, the distance between the two cities is 3 inches. Extra Practice Course 2B 07

5 b) Let x miles be the actual distance. inch : 2 miles. inches : x miles in.. in. 2 mi x mi 2 ẋ? x.? 2 x 87. The actual distance between these two cities is 87. miles.. in. 7. Scale factor 6 in. 3 The scale factor of the reduction is Let y be the length on the map in inches. inch : 2 miles y inches : 2 miles in. y in. 2 mi 2 mi y 2 2 2y 2 2y y.68 On the map, the length of the river is.68 inches. 9. Let x be the actual length of Manila Creek Road in miles inch : miles 3. inches : x miles in. 3. in. mi x mi 3. x x 3. x 7 The actual length of Manila Creek Road is 7 miles. 0. Map length : Actual length in. : 8 miles Map area : Actual area in 2 : 8 2 mi 2 Let x represent the area of the farm on the map in square inches. Area of farm on map Actual area of farm 32 x x 80 32x x 2. On the map, the area of the farm is 2. square inches.. a) Map length : Actual length in. : 9 ft Map area : Actual area in 2 : 9 2 mi 2 Let x represent the actual area of the basketball court in square feet. Area of basketball court onblueprint Actual area ofbasketballcourt 8 8 x 8 x 8 8 x, 698 The actual area of the basketball court is,698 square feet. b) Let y be the actual length of the basketball court. in. : 9 ft 0. in. : y ft in. 0. in. 9 ft y ft 0. 9 y y 9 0. y The actual length of the basketball court is 93.6 feet. c) Length Width Area Area Width Length, The actual width of the court is about 0 feet. 08 Answers