 # Chapter 9: Lesson 4: Solving Percent Problems with Proportions

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Chapter 9: Lesson 4: Solving Percent Problems with Proportions
Objective: Learn to use proportions to solve percent problems.

Another way to solve percent problems is by using proportions.
Steps: First re-write percents as fractions by writing them over a 100. Then use the information in the problem to write the other ratio. Multiply to find the cross products. Use the inverse operation. Solve for the variable. P = is of

Example 1: 45 is what percent of 90? P = is 100 of P = 45 100 90
90P = 45 x 100 90P = P = %

Example 2: P = is 38 = 52 52 is 38% of what number? 100 of 100 N
38 = 52 N 38 N = 5200 N =

Example 3: What number is 47% of 280? p = is 100 of 47 = N 100 280
100N = 47 × 280 100N = 13,160 N =

Homework: Use proportions to solve percent exercises.
What number is 70% of 45? 15 is 25% of what number? What number is 75% of 125? 7 is what percent of 77? What number is 23% of 75?