Ratio and Proportions

Ratios & Proportions: Review

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When two ratios are equal, we say they form a proportion.  You can tell if two ratios are equal by comparing the cross products.

Multiple Choice

$$\frac{10}{16}\ \ \ \ \ \frac{5}{8}$$  

• $$=$$  

• $$\ne$$  

Multiple Choice

$$\frac{4}{8}\ \ \ \ \ \frac{2}{3}$$  

• $$=$$  

• $$\ne$$  

Multiple Choice

$$\frac{6}{8}\ \ \ \ \ \frac{9}{12}$$  

• $$=$$  

• $$\ne$$  

Multiple Choice

$$\frac{12}{20}\ \ \ \ \ \frac{3}{5}$$  

• $$=$$  

• $$\ne$$  

Multiple Choice

$$\frac{10}{12}\ \ \ \ \ \frac{15}{18}$$  

• $$=$$  

• $$\ne$$  

Multiple Choice

$$\frac{10}{12}\ \ \ \ \ \frac{2}{3}$$  

• $$=$$  

• $$\ne$$  

Multiple Choice

$$\frac{5}{9}\ \ \ \ \ \frac{15}{27}$$  

• $$=$$  

• $$\ne$$  

Multiple Choice

Do these ratios form a proportion?

$$\frac{3}{12}\ \ \ \ \ \frac{10}{30}$$  

• yes

•  no

Multiple Choice

Do these ratios form a proportion?

$$\frac{7}{16}\ \ \ \ \ \frac{42}{66}$$  

• yes

•  no

Multiple Choice

Do these ratios form a proportion?

$$\frac{11}{12}\ \ \ \ \ \frac{66}{72}$$  

• yes

•  no

You can use cross multiplication to find an unknown term in a proportion.

Fill in the Blank

Solve for n.

$$\frac{12}{n}=\frac{20}{25}$$  

Fill in the Blank

Solve for n.

$$\frac{5}{8}=\frac{n}{24}$$  

Fill in the Blank

Solve for n.

$$\frac{2}{3}=\frac{16}{n}$$  

Fill in the Blank

Solve for n.

$$\frac{12}{14}=\frac{n}{21}$$  

Fill in the Blank

Solve for n.

$$\frac{n}{10}=\frac{6}{15}$$  

Fill in the Blank

Solve for n.

$$\frac{5}{n}=\frac{10}{16}$$  

Fill in the Blank

Eldon can ride his bike 15 miles in 2 hours. How many miles can he ride in 7 hours?

Fill in the Blank

Lacy can in-line skate 9 miles in an hour. How many hours will it take her to do 36 miles.

Fill in the Blank

Karen and Patrick worked together stringing beads for necklaces. If they can string 50 beads in 9 minutes, how long will it take them th string 750 beads?