Section 6-4: Solving Section 6-4: Solving Percent ProblemsPercent Problems

Review Lessons 7.1 and 7.2: Rates, Ratios, and Review Lessons 7.1 and 7.2: Rates, Ratios, and ProportionsProportions

Standards: AF 4.1 and NS 1.3Standards: AF 4.1 and NS 1.3Objectives: Find Percents.Objectives: Find Percents.

Find the base or part of the base.Find the base or part of the base.

Rate and Ratio ReviewRate and Ratio Review

RatiosRatios

1) 5 inches to 2 feet

2) 5 : 20 people

RatesRates

1) 6 gallons for $6.75

2) Sold 120 rings in 8 h

34

50)km

m

Proportion ReviewProportion Review

13

4

12)b

Percent ProblemsPercent Problems

• Use proportions to solve most percent problems.

a

b

p

parto fbase

Base

Percen t

100

100

Percent Problems: Part of the Percent Problems: Part of the BaseBase

• What is 16% of 50?What is 16% of 50?

• You could change the percent to a decimal and multiply.

• You could set up a proportion:

a

50

16

100

a

b

p

parto fbase

Base

Percen t

100

100

Percent Problems: Part of the Percent Problems: Part of the basebase

1) What is 24% of 50?1) What is 24% of 50?a

b

p

parto fbase

Base

Percen t

100

100

Percent Problems: BasePercent Problems: Base

• Finding the BaseFinding the Base

• Do the same thing, but solve for b.

• 90 is 75% of what 90 is 75% of what number?number?

a

b

p

parto fbase

Base

Percen t

100

100

Percent Problems: BasePercent Problems: Base

2) 66 is 120% of what number?2) 66 is 120% of what number?a

b

p

parto fbase

Base

Percen t

100

100

Percent Problems: PercentPercent Problems: Percent

• What if you don’t know the percent?

• Well, you can use the same proportion, but solve for the percent.

• 17 is what percent 17 is what percent of 20?of 20?

Percent Problems: PercentPercent Problems: Percent

• Find the percent.

1)1) 21 is what percent of 21 is what percent of 30?30?

2)2) On a 50 point quiz, On a 50 point quiz, you received 48 you received 48 points. What percent points. What percent did you receive?did you receive?

3) On a 40 point quiz, you 3) On a 40 point quiz, you received 38 points plus received 38 points plus 6 bonus points. What is 6 bonus points. What is the percent?the percent?