Percents and Proportions

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Percents and Proportions

• Lesson 9.2

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Solving Percent Problems
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Solving Percent Problems

• You can represent a is p percent of b with the
  proportion
• a p
• b 100
• Where a is part of the base b and p is the
  percent.

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Solving Percent Problems

• What percent of 3 is 1?

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Solving Percent Problems

• 1.) Write proportion
• 2.) Substitute 1 for a and 3 for b.

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Solving Percent Problems

• 3.) Multiply each side by 100.
• 4.) Simplify

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Solving Percent Problems

• 1.) What percent of 40 is 16?

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Solving Percent Problems

• In classroom of 25 students, 16 students were
  wearing sandals. What percent were wearing
  sandals?

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Solving Percent Problems
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Finding a Part of a Base
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Finding a Part of a Base

• In a survey, 525 teenagers were asked to name the
  water sport that they would most like to try, and
  20 said surfing. How many teens said surfing?

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Finding a Part of a Base

• Use a proportion.
• 1.) Write proportion

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Finding a Part of a Base

• 2.) Substitute 525 for b and 20 for p.

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Finding a Part of a Base

• 3.) Cross multiply to find the answer.

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Finding a Part of a Base

• 1.) What number is 76 of 25.
• 2.) What number is 5 of 400.

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Finding a Base

• 42 is 30 of what number?

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Finding a Base

• 1.) Write proportion.
• 2.) Substitute 42 for a and 30 for p.

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Finding a Base

• 3.) Cross Multiply.
• 4.) Solve

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Finding a Base

• 1.) 18 is 45 of what number?

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