Proportions Lesson 5.2

Proportions

Lesson 5.2

Proportions

• A proportion is an equation stating that two ratios are equivalent. Two quantities that form a proportion are proportional.

•  $\frac{2}{3}=\frac{4}{6}$  

Determining Whether Ratios Form a Proportion

• Tell whether  $\frac{6}{4}$  and  $\frac{8}{12}$  form a proportion.

• Simplify each fraction to compare.

Determining Whether Two Quantities are Proportional

• Tell whether x and y are proportional. 

• Compare each ratio x to y in simplest form.

Multiple Choice

Tell whether the ratios form a proportion.

 $\frac{1}{2},\ \frac{5}{10}$  

• yes

• no

Multiple Choice

Tell whether the ratios form a proportion.

 $\frac{4}{6},\frac{18}{24}$  

• yes

• no

Multiple Choice

Tell whether the ratios form a proportion.

 $\frac{25}{20},\frac{15}{12}$  

• yes

• no

Multiple Choice

Tell whether the ratios form a proportion.

 $\frac{10}{3},\frac{5}{6}$  

• yes

• no

Multiple Choice

Tell whether x and y are proportional.

• yes

• no

Identifying Proportional Relationships

• You swim your first 4 laps in 2.4 minutes. You complete 16 laps in 12 minutes. Is the number of laps proportional to your time?

• Set up a rate for each.

• Find the unit rate and compare OR use cross products to compare.

Multiple Choice

You read the first 20 pages of a book in 25 minutes. You read 36 pages in 45 minutes. Is the number of pages proportional to your time?

• yes

• no