Solving Proportions

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. For example, if a/b = c/d, then a, b, c, and d are in proportion.

Tags

CCSS.7.RP.A.2A

Front

How do you solve a proportion?

Back

To solve a proportion, you can use cross-multiplication. If a/b = c/d, then a*d = b*c.

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CCSS.7.RP.A.2A

Front

What is cross-multiplication?

Back

Cross-multiplication is a method used to solve proportions by multiplying the numerator of one ratio by the denominator of the other ratio.

Front

If 3/4 = x/12, what is x?

Back

x = 9. (Cross-multiply: 3*12 = 4*x, so 36 = 4x, and x = 36/4 = 9.)

Tags

CCSS.7.RP.A.2B

Front

What is the first step in solving a proportion?

Back

The first step is to set the two ratios equal to each other.

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CCSS.7.RP.A.3

Front

What does it mean if two ratios are equivalent?

Back

If two ratios are equivalent, it means they represent the same relationship between quantities.

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CCSS.6.RP.A.3A

Front

How can you check if your solution to a proportion is correct?

Back

You can check your solution by substituting it back into the original proportion to see if both sides are equal.

Tags

CCSS.6.EE.B.7

Front

What is a unit rate?

Back

A unit rate is a ratio that compares a quantity to one unit of another quantity, such as miles per hour.

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CCSS.6.RP.A.1

CCSS.6.RP.A.2

Front

How do you find a unit rate from a proportion?

Back

To find a unit rate, divide the numerator by the denominator to express the ratio as a quantity per one unit.

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CCSS.6.RP.A.1

CCSS.6.RP.A.2

Front

If 5 apples cost $2, what is the cost of 1 apple?

Back

The cost of 1 apple is $0.40. (Unit rate: $2/5 apples = $0.40 per apple.)

Tags

CCSS.6.RP.A.1

CCSS.6.RP.A.2