Ratio, Rates, & Proportions

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Ratio, Rates, & Proportions

Ratios A ratio is a comparison of two numbers.
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 don’t always have identical meanings to other fractions***

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

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

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. Roses to iris Daisies to roses Iris to daisies all flowers to roses 18 to 24 3 to 4 24 to 16 3 to 2 16 to 18 8 to 9 58 to 8 29 to 9

is not written as a mixed number:
9 Explain why the ratio is not written as a mixed number: 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

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

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

Unit Rates A unit rate is a rate per one unit. In unit rate the denominator is always one. Example: Miguel types 180 words in 4 min. How many words can he type per minute? or words per minute 45 = rate unit rate word form

Unit rates make it easier to make comparisons.
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

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

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

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

Complex fractions are fractions that have fractions within them
.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)

TRY the FOLLOWING Write each rate
TRY the FOLLOWING Write each rate. Then determine the unit rate and write in both fraction and word form 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? Doug entered a canoe race. He rowed miles in hour. What is his average speed? 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? 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. \$5.82 per yard 8 costumes 7mph 3000 ft per hour

Comparing Unit Rates Dario has two options for buying boxes of pasta
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 \$1 is the price per box Price per box CM - \$0.86 per box SF - \$0.83 per box

Proportions

You can determine proportionality by comparing ratios
Two quantities are proportional if they have a constant ratio or unit rate. You can determine proportionality by comparing ratios 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 (\$) 18 36   54  72 Time (h) 1 2 3 4 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.

Cost (\$) 10 17 24 31 Tickets Ordered 1 2 3 4
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 (\$) 10 17 24 31 Tickets Ordered 1 2 3 4 The rates are not equivalent. This means the total cost of the tickets is not proportional to the number of tickets sold.

Use the recipe to make fruit punch
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 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 Sugar 1 1 ½ 2 Envelopes of Mix 3 4

Solving Proportions

Determine if the following ratios are proportional?
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, 340 ≠ Yes, 72 = 72

b. 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. Example: Determine if the two ratios are proportional: c. Yes 72 = 72 No 32 = 30 No 30 = 70

Example: Determine the value of x:
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?” 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 3 pounds \$247.50 \$8.25 per hour

Coordinate Plane Review

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

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 II x - coordinate I III IV

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) I II IV III

Steps for Graphing

Draw and label the x and y axis – don’t forget your arrows
Make a table of values to represent the problem. Be sure to include the values: 0, 1, and 2 Graph your order pairs- you need at least 3 points to make a line Draw a line through the points – don’t forget your arrows If the line is straight and goes through the origin, then the quantities are proportional

Yes – it is a straight line through the origin
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. Number of Minutes 1 2 3 Number of Feet 6 12 18 y Yes – it is a straight line through the origin x

No – it is not a straight line and it doesn’t go through the origin
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. Number of Minutes 1 2 3 Number of Feet 4 8 13 y No – it is not a straight line and it doesn’t go through the origin x

Slope

.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

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

Tell whether the slope is positive or negative . Then find the slope

Use the given slope and point to graph each line

Use the given slope and point to graph each line

Use the given slope and point to graph each line

Rate of Change (Slope)

For graphs, the rate of change (slope) is constant ( a straight line)
.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)

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

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

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

Proportional Relationships

For graphs, the rate of change (slope) is constant ( a straight line)
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)

This table represents a direct variation and is proportional
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

This table represents a direct variation and is proportional
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

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

Proportional Linear Function
Equation: y = 2x

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

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.

25:1 or 25 computers built per hour
Try the following 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 25:1 or 25 computers built per hour

A charter bus travels 210 miles in 3½ hours
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

Determine whether the linear function is a direct variation
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

Janelle planted ornamental grass seeds
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

Dusty earns \$0.50 per paper he delivers
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

The submarine is descending at a rate of 2.5 meters per minute
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

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

Fill in the table for each proportional relationship
Five Gala apples cost \$2 Tess rides her bike at 12 mph Apples 5 10 15 Cost  0 \$2 \$4 \$6 Apples 5 10 15 Cost \$2 Hours 1 2 3 Miles  0 12 24 36 Hours 1 2 3 Miles 12

An Elm tree grows 8 inches each year.
Draw the graph of the proportional relationship between the two quantities An Elm tree grows 8 inches each year. Height (in.) 8 4 Years

Savings Account Balance (\$)
Draw the graph of the proportional relationship between the two quantities David adds \$3.00 to his savings account each week Savings Account Balance (\$) 2 1 Weeks

Slope, Rate of Change, Graphs & Tables

Since it cost \$8 per car the equation would be m = 8c
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

The approximate rate of change is 9.7 miles per minute
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

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

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

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)  0  1  2  3  4  5  Seconds (x) 10 15 20  25

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

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

Finish the rest for Homework 