Checking for Proportionality

Checking for Proportionality

Learning Target

• I can determine if two ratios are proportionate.

Multiple Choice

Solve the proportion below.

 $\frac{3}{7}=\frac{t}{42}$  

• t = 18

• t = 15

• t = 12

• t = 9

Multiple Choice

1 cup of rice calls for 2.25 cups of water. If you only have 0.75 cups of rice, how much water is needed?

• 1 cup of water

• 3 cups of water

• 1.69 cups of water

• 1.125 cups of water

 $\frac{2}{3}=\frac{4}{5}$  

Determine if the proportion above is proportional (equal)

Proportional Relationships

• 
  
   $\frac{2}{3}=\frac{4}{5}$  
  

• Use cross products to determine.

•  $\left(2\right)\left(5\right)=\left(3\right)\left(4\right)$  

•  $10\ne12$  

• The two ratios are not proportional

Proportional Relationships

•  $\frac{3}{4}=\frac{15}{20}$  

• Use cross products to determine if proportional

•  $\left(3\right)\left(20\right)=\left(4\right)\left(15\right)$  

•  $60=60$  

• The two ratios are proportional

 $\frac{4}{5}=\frac{8}{11}$  

Use Cross Products to Determine if the Ratios are Proportional

Multiple Choice

Are the ratios equal?

 $\frac{5}{6}=\frac{25}{30}$  

• They are proportional

• They are NOT proportional

• They are possibly proportional

Multiple Choice

What is the common factor to create the equal proportion?

 $\frac{5}{6}=\frac{25}{30}$  

• 5

• 6

• 2

• 10