1. Copyright © Ed2Net Learning, Inc.1 Proportion & Scale Drawings Grade 6

2. Copyright © Ed2Net Learning, Inc.2 Find the unit rate: 1. 200 miles in 5 hours 2. $6.20 for 5 pounds 3. 2 cups for 36 cookies 4. 150 tickets in 5 days 5. 24 people in 8 cars Warm up

3. Copyright © Ed2Net Learning, Inc.3 Let Us Review our last lesson  A rate is a ratio that is used to compare different kinds of quantities.  A unit rate describes how many units of the first type of quantity corresponds to one unit of the second type of quantity.  A unit price is a rate comparing the price of an item to its unit of measure.  To find the unit price divide the total cost by the number of items bought.

4. Copyright © Ed2Net Learning, Inc.4 Let Us Review  Rate = Distance/time To find rate divide distance by time  Time = Distance/rate To find time divide distance by rate

5. Copyright © Ed2Net Learning, Inc.5 Find the population density of a county with 56,000 residents and an area of 636 square miles. About 88 people per square mile Example

6. Copyright © Ed2Net Learning, Inc.6 What is a Proportion?  A proportion is an equation that states that two ratios are equal.  Proportions always have a equal sign.  Example of proportion: 2 6 3 9 = Let’s get Started

7. Copyright © Ed2Net Learning, Inc.7  We can write proportions in two ways:  In a proportion 2:3 = 6:9  First and last terms (i.e. 2 and 9) are called extremes.  Second and third terms (i.e. 3 and 6) are called means. Rule: In a proportion, the product of the means equals to the product of the extremes. Or 2:3 = 6:9 2 6 3 9 =

8. Copyright © Ed2Net Learning, Inc.8 Scale Drawings What is a scale drawing?  A scale drawing is a drawing of an object with dimensions proportional to those of the actual object.  The scale of the drawing is the ratio of the size of the drawing to the actual size of the object.  Architects and map-makers use scale drawings.

9. Copyright © Ed2Net Learning, Inc.9 Example 1 On a map 1 in = 2 mile, What does 5 in equals?. You can establish a proportion: Now cross-multiply, we will get 1 x x = 2 x 5 After simplification we will get. x = 10 miles. 1 5 2 x =

10. Copyright © Ed2Net Learning, Inc.10 Example 2 On a scale drawing if 1 in = 20 yards, What does 100 yards equals?. You can establish a proportion: Now cross-multiply, we will get 1 x 100 = y x 20 After simplification we will get. 100 = 20y so y = 5 in 1 y 20 100 =

11. Copyright © Ed2Net Learning, Inc.11 Let’s take a break!!

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13. Copyright © Ed2Net Learning, Inc.13 Your Turn On a scale drawing if 1 inch = 3 feet then : 1. 4 inches = 2. 3 inches = 3. 10 inches = 4. 1/3 inch = 5. 12 inches =

14. Copyright © Ed2Net Learning, Inc.14 Your Turn Solve: 6. A computer circuit board 4 cm wide ; 1 cm: 0.2 cm 7. 15feet by 25feet 8. 6/13 = 8/n 9. A garage door 16feet wide ; 2 inches: 1 foot 10. A gear 3 5/8 in. across; 4in: ½ in.

15. Copyright © Ed2Net Learning, Inc.15 1. Out of every 100 U.S. households having teens, 8 of them will purchase camping equipment sometimes during the year. Of the 64.5million households having teens in the U.S., How many will purchase camping equipment during the year?

16. Copyright © Ed2Net Learning, Inc.16 2. An invention by a NASA scientist Valerie Thomas may make TV’s have 3 – D images. A drawing for her patent of the illusion transmitter is 8.4cm. Tall. If the scale is 1cm : 2.2 cm, what will the actual length of the transmitter be?

17. Copyright © Ed2Net Learning, Inc.17 3. The first Jumbo Jet was the Boeing 747, which is 70.5 m long. The wingspan of a 747 is 60 meters. A model 747 has a wingspan of 80 cm. What should the length of the model be?

18. Copyright © Ed2Net Learning, Inc.18 Let Us Review  A proportion is an equation that states that two ratios are equal.  We can write proportions in two ways. or 2:3 = 6:9 In a proportion, the product of the means equals to the product of the extremes. 2 6 3 9 =

19. Copyright © Ed2Net Learning, Inc.19 Let Us Review  A scale drawing is a drawing of an object with dimensions proportional to those of the actual object.  The scale of the drawing is the ratio of the size of the drawing to the actual size of the object.  Architects and map-makers use scale drawings.

20. Copyright © Ed2Net Learning, Inc.20 You did Great Today! Be sure to practice what you have learned today