Proportions

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you set up a proportion to solve a problem?

Back

To set up a proportion, you can use the formula a/b = c/d, where a and b are the first ratio, and c and d are the second ratio.

Front

If 3 pounds of hamburger meat costs $6, how much does 10 pounds cost?

Back

$20

Front

If Mary saves $17.50 in 3 weeks, how much will she save in 15 weeks?

Back

$87.50

Front

What is the relationship between the quantities in a proportion?

Back

The relationship is that the cross products are equal; for example, in a/b = c/d, then a*d = b*c.

Front

How do you find an unknown in a proportion?

Back

You can cross-multiply and solve for the unknown.

Front

If a recipe calls for 1.5 cups of milk for 3 cups of flour, how much milk is needed for 5 cups of flour?

Back

2.5 cups of milk.

Front

What is the expected number of homes with a computer if 13 out of 20 homes have one on a street with 60 homes?

Back

39 homes.

Front

If a 12-ounce shampoo bottle lasts 16 weeks, how long will an 18-ounce bottle last?

Back

24 weeks.

Front

What is the formula for finding the unit rate?

Back

The unit rate is found by dividing the numerator by the denominator.