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Ratio, Rates, & Proportions. Ratios A ratio is a comparison of two numbers. o Example: Tamara has 2 dogs and 8 fish. The ratio of dogs to fish can be.

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Presentation on theme: "Ratio, Rates, & Proportions. Ratios A ratio is a comparison of two numbers. o Example: Tamara has 2 dogs and 8 fish. The ratio of dogs to fish can be."— Presentation transcript:

1 Ratio, Rates, & Proportions

2 Ratios A ratio is a comparison of two numbers. o Example: Tamara has 2 dogs and 8 fish. The ratio of dogs to fish can be written in three different ways. *** Be careful with the fraction ratios – they dont always have identical meanings to other fractions ***

3 There are two different types of ratios o.Part-to-Part Ratios Example: Tamaras dogs to cats is 2 to 8 or 1 to 4 o.Part –to-Whole Ratios Example: Tamaras dogs to total pets is 2 to 10 or 1 to 5

4 Try the following Apples to bananas There are 12 apples and 3 bananas So the ratio of apples to bananas is 4:1, 4 to 1, OR Oranges to apples There are 15 oranges and 12 apples So the ratio of oranges to apples is 5:4, 5 to 4, OR

5 1.Roses to iris 3.Daisies to roses 2.Iris to daisies 4. all flowers to roses A large bouquet of flowers is made up of 18 roses, 16 daisies, and 24 irises. Write each ratio in all three forms in simplest form. Identify which ratios are part-to- part and which ratios are part-to-whole. 18 to 24 3 to 4 58 to 8 29 to 9 16 to 18 8 to 9 24 to 16 3 to 2

6 The ratio is comparing two number. If you changed it to a mixed number it would no longer be a comparison. This is why fraction ratios are tricky Explain why the ratio 9 is not written as a mixed number:

7 Comparing Ratios Compare ratios by writing in simplest form o Are these ratios equivalent? 250 Kit Kats to 4 M&Ms and 500 Kit Kats to 8 M&Ms o 12 out of 20 doctors agree and 12 out of 30 doctors agree o The ratio of students in Ms. Bs classes that had HW was 8 to 2 and 80% of Mrs. Longs class had HW = =

8 Rates A rate is a ratio that compares two different quantities or measurements. Rates can be simplified Rates us the words per and for o Example: Driving 55 miles per hour o Example: 3 tickets for $1

9 Unit Rates A unit rate is a rate per one unit. In unit rate the denominator is always one. o Example: Miguel types 180 words in 4 min. How many words can he type per minute? = or words per minute rate unit rate word form

10 Unit rates make it easier to make comparisons. o Example: Taylor can type 215 words in 5 min How many words can he type per minute? Who is the faster typist? How much faster? Taylor is 2wpm faster than Miguel

11 1.Film costs $7.50 for 3 rolls 3.90 students and 5 teachers 5.**Snowfall of 12 ¾ inches in 4 ½ hours. 7.Ian drove 30 miles in 0.5 hours 2.Drive 288 miles on 16 gallons of gas. 4.Earn $49 for 40 hours of work 6.Use 5 ½ quarts of water for every 2 lbs of chicken 8.Sarah drove 5 miles in 20 minutes Try the Following $2.50 per roll 15 mph 2 ¾ quarts per lb $1.23 per hour 18 mpg 18 students per teacher 2 5/6 per hour 60 mph

12 Complex Unit Rates Suppose a boat travels 30 miles in 2 hours o How do you write this rate? Suppose a boat travels 12 miles in 2/3 hours o How do you write this as a rate? o How do you write this as a division problem? o Determine the unit rate: 18mph

13 Suppose a boat travels 8 ¾ miles in 5/8 hours. o How do you write this as a rate? o How do you write this as a division problem? o Determine the unit rate: 14 mph

14 .Complex fractions are fractions that have fractions within them. They are either in the numerator, denominator, or both. Divide complex fractions by multiplying (keep, change, change)

15 1.Mary is making pillows for her Life Skills class. She bought yards of fabric. Her total cost was $16. What was the cost per yard? 3.Doug entered a canoe race. He rowed miles in hour. What is his average speed? 3.Mrs. Robare is making costumes for the school play. Each costume requires 0.75 yards of fabric. She bought 6 yards of fabric. How many costumes can Mrs. Robare make? 4. A lawn company advertises that they can spread 7,500 square feet of grass seed in hours. Find the number of square feet of grass seed that can be spread in an hour. TRY the FOLLOWING Write each rate. Then determine the unit rate and write in both fraction and word form $5.82 per yard 3000 ft per hour 7mph 8 costumes

16 Comparing Unit Rates Dario has two options for buying boxes of pasta. At CornerMarket he can buy seven boxes of pasta for $6. At SuperFoodz he can buy six boxes of pasta for $5. He divided 7 by 6 and got at CornerMarket. He then divided 6 by 7 and got He was confused. What do these numbers tell him about the price of boxes of pasta at CornerMarket? Decide which makes more sense to you Compare the two stores prices. Which store offers the better deal? is the number of boxes you can get for $ is the price per box Price per box CM - $0.86 per box SF - $0.83 per box

17 Proportions

18 Two quantities are proportional if they have a constant ratio or unit rate. You can determine proportionality by comparing ratios o Andrew earns $18 per hour for mowing lawns. Is the amount he earns proportional to the number of hours he spends mowing? Make a table to show these amounts For each number of hours worked, write the relationship of the amount he earned and hour as a ratio in simplest form. Are all the rates equivalent? Earnings ($) Time (h)1234 Since each rate simplifies to 18, they are all equivalent. This means the amount of money Andrew earns is proportional to the number of hours he spends mowing.

19 o Uptown Tickets charges $7 per baseball game ticket plus $2 processing fee per order. Is the cost of an order proportional to the number of tickets ordered? Make a table to show these amounts For each number of tickets, write the relationship of the cost of the and the number of tickets ordered. Are all the rates equivalent? Cost ($) Tickets Ordered1234 The rates are not equivalent. This means the total cost of the tickets is not proportional to the number of tickets sold.

20 o Use the recipe to make fruit punch. Is the amount of sugar used proportional to the amount of mix used? Explain. Yes, they all reduce to ½ o In July, a paleontologist found 368 fossils at a dig. In August, she found about 14 fossils per day. Is the number of fossils the paleontologist found in August proportional to the number of days she spent looking for fossils that month? No, July average fossils per day Cups of Sugar½11 ½2 Envelopes of Mix1234

21 Solving Proportions

22 A proportion is two equivalent ratios When solving proportions we must first ask ourselves – What are we comparing A lemonade recipe calls for ½ cup of mix for every quart of water. If Jeff wanted to make a gallon of lemonade, is 2 cups of mix proportional for this recipe? YES Determine if the following ratios are proportional? No, Yes, 72 = 72

23 Proportionality can also be determined between two ratios by simplifying or comparing their cross products If they reduce to the same ratio, or their cross products are the same, then they are proportional You can also solve proportions for a missing variable by cross multiplying. o Example: Determine if the two ratios are proportional: b. c. Yes 72 = 72 No 32 = 30 No 30 = 70

24 o Example: Determine the value of x: o Example: A stack of 2,450 one-dollar bills weighs five pounds. How much do 1,470 one-dollar bills weigh? Set up a proportion – ask ourselves what are we comparing? o Example: Whitney earns $ for 25 hours of work. At this rate, how much will Whitney earn for 30 hours of work? How much does Whitney earn per hour? x = 60 $8.25 per hour 3 pounds $247.50

25 Coordinate Plane Review

26 The Coordinate Plane y-axis Origin x-axis Quadrant I Quadrant II Quadrant III Quadrant IV

27 Ordered Pair: is a pair of numbers that can be used to locate a point on a coordinate plane

28 Ordered Pairs Ordered Pair: is a pair of numbers that can be used to locate a point on a coordinate plane. –Example: (3, 2) y - coordinate x - coordinate I II IIIIV

29 Graph the following ordered pairs on the coordinate plan and state the quadrants the points are located in (3, 2) (-5, 4) (6, -4) (-7, 7) II I IV III

30 Steps for Graphing

31 1. Draw and label the x and y axis – dont forget your arrows 2. Make a table of values to represent the problem. Be sure to include the values: 0, 1, and 2 3. Graph your order pairs- you need at least 3 points to make a line 4. Draw a line through the points – dont forget your arrows 5. If the line is straight and goes through the origin, then the quantities are proportional

32 Example: The slowest mammal on Earth is the tree sloth. It moves at a speed of 6 feet per minute. Determine whether the number of feet the sloth moves is proportional to the number of minutes it moves by graphing. Explain your reasoning. y x Number of Minutes123 Number of Feet61218 Yes – it is a straight line through the origin

33 Example: The table below shows the number of calories an athlete burned per minute of exercise. Determine whether the number of calories burned is proportional to the number of minutes by graphing. Explain your reasoning. y x Number of Minutes123 Number of Feet4813 No – it is not a straight line and it doesnt go through the origin

34 Slope

35 .Slope is the rate of change between any two points on a line The sign of the slope tells you whether the line is positive or negative. You can find slope of a line by comparing any two points on that line Slope is the or

36 Positive Slope The line goes up 3 (rise) and over 1 (run). Slope = 3 Negative Slope The line goes down 2 (rise) and over 1 (run). Slope = -2

37 Tell whether the slope is positive or negative. Then find the slope Negative Slope = -1 Positive Slope = 4/3

38 Use the given slope and point to graph each line

39

40

41 Rate of Change (Slope)

42 .Rate of change (slope) describes how one quantity changes in relation to another. For graphs, the rate of change (slope) is constant ( a straight line)

43 Tell whether each graph shows a constant or variable rate of change ConstantVariable

44 Tell whether each graph shows a constant or variable rate of change Constant Variable

45 Tell whether each graph shows a constant or variable rate of change ConstantVariable

46 Proportional Relationships

47 A proportional relationship between two quantities is one in which the two quantities vary directly with one another (change the same way). This is called a direct variation. For graphs, the rate of change (slope) is constant ( a straight line)

48 Determine whether each table represents a direct variation by comparing the ratios to check for a common ratio This table represents a direct variation and is proportional This table does NOT represent a direct variation and is NOT proportional

49 Determine whether each table represents a direct variation by comparing the ratios to check for a common ratio This table does NOT represent a direct variation and is NOT proportional This table represents a direct variation and is proportional

50 The equations of such relationships are always in the form y = mx and when graphed produce a line that passes through the origin.

51 Proportional Linear Function Equation: y = 2x

52 Non- Proportional Linear Function Equation: y = 2x – 1

53 In the equation y=mx, m is the slope of the line, and its also called the unit rate, the rate of change, or the constant of proportionality of the function.

54 The number of computers built varies directly as the numbers of hours the production line operates. What is the ratio of computers build to hours of production Try the following 25:1 or 25 computers built per hour

55 A charter bus travels 210 miles in 3½ hours. Assuming that the distance traveled is proportional to the time traveled, how far will the bus travel in 6 hours? 360 miles

56 Determine whether the linear function is a direct variation. If so stat the constant of variation. Yes this is a direct variation because there is a constant of variation of 58 mph

57 Janelle planted ornamental grass seeds. After the grass breaks the soil surface, its height varies directly with the number of days. What is the rate of growth? 0.75 inches per day

58 The amount Dusty earns is directly proportional to the number of newspapers he delivers. How much does Dusty earn for each newspaper delivery? Dusty earns $0.50 per paper he delivers

59 Ten minutes after a submarine is launched from a research ship, it is 25 meters below the surface. After 30 minutes, the submarine has descended 75 meters. At what rate is the submarine driving? The submarine is descending at a rate of 2.5 meters per minute

60 The Stratton family rented 3 DVDs for $ The next weekend, they rented 5 DVDs for $ What is the rental fee for a DVD? The rental fee for DVDs is $3.49 per DVD

61 Five Gala apples cost $2 Tess rides her bike at 12 mph Fill in the table for each proportional relationship Apples Cost $2 Hours0123 Miles 12 Apples Cost 0$2$4$6 Hours0123 Miles

62 An Elm tree grows 8 inches each year. Draw the graph of the proportional relationship between the two quantities Years Height (in.)

63 David adds $3.00 to his savings account each week Draw the graph of the proportional relationship between the two quantities Savings Account Balance ($) Weeks

64 Slope, Rate of Change, Graphs & Tables

65 The table shows the amount of money a Booster Club made washing cars for a fundraiser. Use the information to find the rate of change in dollars per car. –Write and equation that shows the money raised m of washing c cars. Since it cost $8 per car the equation would be m = 8c

66 The table shows the number of miles a plane traveled while in flight. Use the information to find the approximate rate of change in miles per minute. The approximate rate of change is 9.7 miles per minute

67 The graph represents the distance traveled while driving a car on the highway. Use the graph to find the rate of change in miles per hour. –Pick two points on the line

68 Write an equation that shows the distance m for the time h. m = 30h

69 The table below shows the relationship between the number of seconds y it takes to hear the thunder after a lightning strike and the distance x you are from the lightning. SKIP THIS QUESTION Distance (y) Seconds (x)

70 Graph the data. Then find the slope of the line. Explain what the slope represents. Water Loss cm) Weeks

71 Graph the data. Then find the slope of the line. Explain what the slope represents. Temperature (˚F) Time

72 Finish the rest for Homework


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