Proportions

Front

What is a proportion?

Back

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

Front

How do you solve a proportion?

Back

To solve a proportion, cross-multiply the two ratios and set the products equal to each other.

Front

What is the formula for finding a missing value in a proportion?

Back

If a/b = c/d, then ad = bc.

Front

If 10 guests cost $9.50, how much does it cost per guest?

Back

$0.95 per guest.

Front

If 13 out of 20 homes have a computer, what is the ratio of homes with computers to total homes?

Back

The ratio is 13:20.

Front

What is the scale factor in a proportion?

Back

The scale factor is the ratio of any two corresponding lengths in two similar geometric figures.

Front

If the ratio of boys to girls is 3:2 and there are 12 boys, how many girls are there?

Back

8 girls.

Front

How do you find the total cost for a different number of guests using proportions?

Back

Set up a proportion based on the known cost and number of guests, then solve for the unknown.

Front

What is the relationship between ratios and proportions?

Back

Ratios compare two quantities, while proportions show that two ratios are equal.

Front

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

Back

$87.50.