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### Proportions

• Ratios that are equal form a proportion.
• The Cross Products Property is true because of the Multiplication Property of Equality.
• There are two ways to solve a proportion. You may be able to create an equivalent proportion by finding equivalent ratios by multiplying or dividing the numerator and denominator by the same number. The second way, the preferred method, is to use cross products and then solve for the missing number by using division.

• 45x = 9 ×10
• 45x = 90
• x = 90 ÷45

• 35x = 20 ×7
• 35x = 140
• x = 140 ÷35

• 5x = 2 ×15
• 5x = 30
• x = 30 ÷5

• 30x = 6 ×20
• 30x = 120
• x = 120 ÷30

• 7x = 13 ×14
• 7x = 182
• x = 182 ÷7

• 16x = 8 ×7
• 16x = 56
• x = 56 ÷16

## You exchange \$ 235 for 1501.97 Chinese Yuan. Find the unit rate of exchange to the nearest hundredth.

• [\$ 235/1501.97] = [\$ 1/e]
• 235e = 1501.97
• e = 1501.97 ÷235

## Does this ratio form a proportion? Explain. [65/25], [13/5]

• [(65 ÷5)/(25 ÷5)] = [13/5]

## A car can travel 155 miles on 5 gallons of gas. How far can the car travel on 7 gallons of gas?

• [155/5] = [x/7]
• 5x = 155 ×7
• 5x = 1085
• x = 1085 ÷5

## You are making a map of the state of Colorado that is to scale. Colorado is approximately 380 miles long and 280 miles wide in real life. If the Colorado on your map is going to be 14 inches wide, how long will it be?

• [380 mi long/280 mi wide] = [(x in long)/14 in wide]
• 280x = 380 ×14
• 280x = 5320
• x = 5320 ÷280

### x = 19 in

*These practice questions are only helpful when you work on them offline on a piece of paper and then use the solution steps function to check your answer.

## Proportions

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