Chapter 5 Ratio and Proportion

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Chapter 5Ratio and Proportion
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Chapter Outline

• Ratios
• Rates
• Proportions
• Proportions and Problem Solving

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5.1

• Ratios

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Section Objectives

• Writing Ratios as Fractions
• Writing Ratios in Simplest form

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Writing Ratios as Fractions
EXAMPLE
Write the ratio of 7 to 12 as a fraction.
SOLUTION
Remember that order is important while writing
ratios.
is not the same as
Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC
COLLEGE MATHEMATICS, 3e Slide 5
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Writing Ratios in Simplest Form
EXAMPLE
Write the ratio 25 to 150 as a fraction in its
simplest form.
SOLUTION
Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC
COLLEGE MATHEMATICS, 3e Slide 6
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5.2

• Rates

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Section Objectives

• Writing Rates as Fractions
• Finding Unit Rates
• Finding Unit Prices

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Writing Rates as Fractions
Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC
COLLEGE MATHEMATICS, 3e Slide 9
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Finding Unit Rates
EXAMPLE
Write 275 miles in 11 hours as a unit rate.
SOLUTION
Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC
COLLEGE MATHEMATICS, 3e Slide 10
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Finding Unit Prices
EXAMPLE
Find the unit price of 0.87 for 3 apples.
SOLUTION
Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC
COLLEGE MATHEMATICS, 3e Slide 11
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5.3
Proportions
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Section Objectives

• Writing Proportions
• Determining Whether Proportions Are True
• Finding Unknown Numbers in Proportions

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Writing Proportions
Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC
COLLEGE MATHEMATICS, 3e Slide 14
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Determining Whether Proportions Are True
EXAMPLE
Determine whether is a true
proportion by cross multiplying.
SOLUTION
Since the cross products are not equal,
are not equivalent proportions.
Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC
COLLEGE MATHEMATICS, 3e Slide 15
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Finding Unknown Numbers in Proportions
Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC
COLLEGE MATHEMATICS, 3e Slide 16
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5.4
Proportions and Problem Solving
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Section Objectives

• Solving Problems by Writing Proportions

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Solving Problems by Writing Proportions
EXAMPLE
There are 76 milligrams of cholesterol in a
3-ounce serving of skinless chicken. How much
cholesterol is in 8 ounces of chicken? (Source
USDA)
SOLUTION
There are milligrams of cholesterol in a
3-ounce serving of skinless chicken.
Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC
COLLEGE MATHEMATICS, 3e Slide 19