Pre-Algebra Chapter 6 - Ramsey School District

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Study Tip Scale Factor When finding the scale factor, be sure to use the same units of measure. The ratio of a length on a scale drawing or model to the corresponding length on the real object is called the scale factor. Suppose a scale model 2 has a scale of 2 inches 16 inches. The scale factor is or 1 1 6 8 . The lengths and widths of objects of a scale drawing or model are proportional to the lengths and widths of the actual object. Example 1 Find Actual Measurements DESIGN A set of landscape plans shows a flower bed that is 6.5 inches wide. The scale on the plans is 1 inch 4 feet. a. What is the width of the actual flower bed? Let x represent the actual width of the flower bed. Write and solve a proportion. plan width → 1 inch 6.5 inches ← plan width actual width → 4 feet x feet ← actual width 1 x 4 6.5 Find the cross products. x 26 Simplify. The actual width of the flower bed is 26 feet. 6.5 in. b. What is the scale factor? To find the scale factor, write the ratio of 1 inch to 4 feet in simplest form. 1 inch 1 inch Convert 4 feet to inches. 4 feet 48 inches 1 1 The scale factor is . That is, each measurement on the plan is the 4 8 4 8 actual measurement. Architecture The exterior of the Lincoln Memorial features 36 columns that represent the states in the Union when Lincoln died in 1865. Each column is 44 feet high. Source: www.infoplease.com Example 2 Determine the Scale ARCHITECTURE The inside of the Lincoln Memorial contains three chambers. The central chamber, which features a marble statue of Abraham Lincoln, has a height of 60 feet. Suppose a scale model of the chamber has a height of 4 inches. What is the scale of the model? Write the ratio of the height of the model to the actual height of the statue. Then solve a proportion in which the height of the model is 1 inch and the actual height is x feet. model height → actual height → 4 inc 60 f hes eet inch ← model height x feet ← actual height 4 x 60 1 Find the cross products. 4x 60 Simplify. 4 x 6 0 4 4 Divide each side by 4. x 15 So, the scale is 1 inch 15 feet. Simplify. www.pre-alg.com/extra_examples Lesson 6-3 Scale Drawings and Models 277
Interior Designer Interior designers plan the space and furnish the interiors of places such as homes, offices, restaurants, hotels, hospitals, and even theaters. Creativity and knowledge of computeraided design software is essential. Online Research For information about a career as an interior designer, visit: www.pre-alg.com/ careers CONSTRUCT SCALE DRAWINGS To construct a scale drawing of an object, use the actual measurements of the object and the scale to which the object is to be drawn. Example 3 Construct a Scale Drawing INTERIOR DESIGN Antonio is designing a room that is 20 feet long and 12 feet wide. Make a scale drawing of the room. Use a scale of 0.25 inch 4 feet. Step 1 Find the measure of the room’s length on the drawing. Let x represent the length. Step 2 Step 3 drawing length → actual length → 0.2 5 in 4 fe ch et x inches 2 0 feet 0.25 20 4 x Find the cross products. 5 4x Simplify. 1.25 x Divide each side by 4. On the drawing, the length is 1.25 or 1 1 4 inches. Find the measure of the room’s width on the drawing. Let w represent the width. drawing length → actual length → 0.2 5 in 4 fe ch et w inches 12 feet 0.25 12 4 w Find the cross products. 3 4w Simplify. 3 4 4 4w Divide each side by 4. 0.75 w Simplify. On the drawing, the width is 0.75 or 3 4 inch. Make the scale drawing. Use 1 -inch grid paper. Since 4 1 1 4 3 4 inches 5 squares and inch 3 squares, draw a rectangle that is 5 squares by 3 squares. ← drawing length ← actual length ← drawing length ← actual length 20 ft 12 ft Concept Check 1. OPEN ENDED Draw two squares in which the ratio of the sides of the first square to the sides of the second square is 1:3. 2. FIND THE ERROR Montega and Luisa are rewriting the scale 1 inch 2 feet in a:b form. Montega 1:36 Luisa 1:24 278 <strong>Chapter</strong> 6 Ratio, Proportion, and Percent Who is correct? Explain your reasoning.
Page 1 and 2: Ratio, Proportion, and Percent •
Page 3 and 4: Ratios and Rates Vocabulary • rat
Page 5 and 6: Study Tip Look Back To review dimen
Page 7 and 8: Standardized Test Practice Extendin
Page 9 and 10: Using Proportions Vocabulary • pr
Page 11 and 12: TEACHING TIP Solve juice in origina
Page 13 and 14: 41. SNACKS The Skyway Snack Company
Page 15: Scale Drawings and Models Vocabular
Page 19 and 20: 21. CRITICAL THINKING What does it
Page 21 and 22: To write a fraction as a percent, w
Page 23 and 24: Practice and Apply Homework Help Fo
Page 25 and 26: A Preview of Lesson 6-5 Using a Per
Page 27 and 28: Using the Percent Proportion • Us
Page 29 and 30: Example 4 Find the Part What number
Page 31 and 32: 25. LIFE SCIENCE Carbon constitutes
Page 33 and 34: Find the percent of each number men
Page 35 and 36: Practice and Apply Homework Help Fo
Page 37 and 38: Using Percent Equations Vocabulary
Page 39 and 40: Simple interest is the amount of mo
Page 41 and 42: 42. CRITICAL THINKING Determine whe
Page 43 and 44: Percent of Change Vocabulary • pe
Page 45 and 46: PERCENT OF DECREASE When the amount
Page 47 and 48: Standardized Test Practice 26. RESE
Page 49 and 50: Probability and Predictions Vocabul
Page 51 and 52: USE A SAMPLE TO MAKE PREDICTIONS No
Page 53 and 54: Standardized Test Practice 37. FOOD
Page 55 and 56: Vocabulary and Concept Check base (
Page 57 and 58: Chapter 6 Study Guide and Review 6-
Page 59 and 60: • Extra Practice, see pages 736-7
Page 61 and 62: Part 1 Record your answers on the a

Pre-Algebra Chapter 6 - Ramsey School District

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