Sec 3.2 Finding Part

1
Sec 3.2 Finding Part

• Objectives
• Know the three elements of a percent problem.
• Learn the basic percent formula.
• Solve for part.
• Recognize the terms associated with base, rate,
  and part.
• Calculate sales tax.
• Learn to standardize the format of percent
  problems.

2

• Percent problems contain three main quantities.
  Usually, two of the three quantities are given
  and the third must be determined.

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The Elements of a Percent Problem

• Part--a portion of the whole
• Base--the whole, or total amount
• Rate--a number followed by

4
The Basic Percent Formula

• Part Base x Rate, or
• P B x R
• Note when solving problems with percents you
  must convert the percent to a decimal before
  performing any computations.

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Solve for part using P B x R

• P B x R
• P 120 x 40

6
Solve for part using P B x R

• P B x R
• P 120 x 40
• P 120 x 0.40

7
Solve for part using P B x R

• P B x R
• P 120 x 40
• P 120 x 0.40
• P 48

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In Solving Word Problems

• Base--is preceded by the word of or on
• Rate-- is followed by a percent sign or the
  word percent
• Part--is usually a portion of the base

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Note the preposition of usually indicates
multiplication, while is means is equal to.

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Problem 18, P. 97

• Kirsten Speed needs 124 credits to graduate. If
  Kirsten has already completed 75 of the credits,
  find the number of credits completed.

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Problem 18, P. 97

• Kelly Melcher needs 124 credits to graduate. If
  Melcher has already completed 75 of the credits,
  find the number of credits completed.

12
Problem 18, P. 97

• Kirsten Speed needs 124 credits to graduate. If
  Melcher has already completed 75 of the credits,
  find the number of credits completed.

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Problem 18, P. 97 cont.

• credits completed is 75 of the credits

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Problem 18, P. 97 cont

• credits completed is 75 of 124

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Problem 18, P. 97 cont

• credits completed 75 x 124

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Problem 18, P. 97 cont

• credits completed 75 x 124
• Part R x B
• Part 75 x 124
• Part 0.75 x 124 93

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Homework Sec 3.2 the even thru 38.