Percentages as Proportional Relationships

Percentages II

Creating proportional relationships to solve problems with percents

Proportional Ratios & Percents

What makes an equation proportional?

Multiple Choice

Which expression is proportional?

• $\frac{90\%\ red}{100\%\ total}=\frac{20\ total}{18\ red}$

• $\frac{90\%\ red}{100\%\ total}=\frac{18\ red}{20\ total}$

Multiple Choice

Which expression is proportional?

• $\frac{10\%\ white}{100\%\ total}=\frac{1\ red}{10\ total}$

• $\frac{10\%\ white}{100\%\ total}=\frac{1\ white}{3\ red}$

• $\frac{10\%\ white}{100\%\ total}=\frac{3\ red}{10\ total}$

• $\frac{10\%\ white}{100\%\ total}=\frac{1\ white}{10\ total}$

How do proportions help us find the unknown?

How to set up percent problems as proportional equation

Multiple Choice

Which proportional relationship best matches the math problem?

What is 30% of 300?

• $\frac{30\%}{100\%}=\frac{300}{ }$

• $\frac{ }{300}=\frac{30\%}{100\%}$

• $\frac{300}{100\%}=\frac{30}{ }$

Multiple Choice

Which proportional relationship best matches the math problem?

20 is ___% of 150

•  $\frac{20\%}{100\%}=\frac{ }{150}$ 

•  $\frac{ }{150}=\frac{20\%}{100\%}$ 

•  $\frac{ }{100\%}=\frac{20}{150}$ 

Multiple Choice

Which proportional relationship best matches the math problem?

___ is 80% of 450

•  $\frac{80\%}{100\%}=\frac{ }{450}$ 

•  $\frac{80\%}{ }=\frac{450}{100\%}$ 

•  $\frac{ }{100\%}=\frac{80}{450}$ 

Reading math problems about percentages

Fill in the Blanks

Multiple Choice

Which proportional set-up best fits this math question?

Wendy has 4 pets. 3 pets are fish. What percentage of Wendy's pets are fish?

• $\frac{4\ pets}{3\ fish}=\frac{ }{100\%\ pets}$

• $\frac{ }{100\%\ pets}=\frac{1\ not\ fish}{4\ pets}$

• $\frac{3\ fish}{4\ pets}=\frac{ }{100\%\ pets}$

• $\frac{3\ fish}{100\%\ pets}=\frac{ }{4\ pets}$

Multiple Choice

Which proportional set-up best fits this math question?

Wendy has 4 pets. 3 pets are fish. What percentage of Wendy's pets are NOT fish?

• $\frac{4\ pets}{3\ fish}=\frac{ }{100\%\ pets}$

• $\frac{ }{100\%\ pets}=\frac{1\ not\ fish}{4\ pets}$

• $\frac{3\ fish}{4\ pets}=\frac{ }{100\%\ pets}$

• $\frac{3\ fish}{100\%\ pets}=\frac{ }{4\ pets}$

Multiple Choice

Which proportional set-up best fits the math question?

60% of Peter's friends dress in animal costumes. Peter has 15 friends. How many friends dressed in animal costumes?

• $\frac{60\%\ \cos tume}{100\%\ friends}=\frac{ }{15\ friends}$

• $\frac{15\ friends}{100\%\ friends}=\frac{60\%\ \cos tume}{ }$

• $\frac{15\ friends}{ }=\frac{60\%\ \cos tume}{100\%\ friends}$

Multiple Choice

Which proportional set-up best fits the math question?

60% of Peter's friends dress in animal costumes. Peter has 15 friends. How many friends did not dress in costume?

•  $\frac{40\%\ \ no\cos tume}{100\%\ friends}=\frac{ }{15\ friends}$ 

•  $\frac{15\ friends}{100\%\ friends}=\frac{40\%\ no\cos tume}{ }$ 

•  $\frac{ }{15\ friends}=\frac{60\%\ \cos tume}{100\%\ friends}$