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.

Tags

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 the proportion 5/x = 15/20?

Back

The first step is to cross-multiply: 5*20 = 15*x.

Tags

CCSS.7.RP.A.2C

Front

What does it mean if two ratios are equivalent?

Back

Two ratios are equivalent if they represent the same relationship between quantities, meaning they can be expressed as a proportion.

Tags

CCSS.6.RP.A.3A

Front

How can you check if two ratios are in proportion?

Back

You can check if two ratios are in proportion by cross-multiplying and seeing if the products are equal.

Tags

CCSS.7.RP.A.2A

Front

If a/b = c/d, what is the relationship between a, b, c, and d?

Back

The relationship is that the product of a and d equals the product of b and c (a*d = b*c).

Tags

CCSS.7.RP.A.2A

Front

What is an example of a real-life situation that can be modeled with proportions?

Back

A real-life example is cooking: if a recipe requires 2 cups of flour for 4 servings, you can find out how much flour is needed for 10 servings using proportions.

Tags

CCSS.7.RP.A.2A

Front

What is the term for the number that is being solved for in a proportion?

Back

The term is called the 'variable' or 'unknown'.

Tags

CCSS.6.EE.B.7