Proportions

Front

What is a proportion?

Back

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

Front

How do you determine if two ratios form a proportion?

Back

Two ratios form a proportion if the cross products are equal.

Front

If 14 sticks of pepperoni are needed for 28 pizzas, how many sticks are needed for 1 pizza?

Back

0.5 sticks of pepperoni.

Front

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

Back

The ratio is 13:20.

Front

What is the cross product of the ratios 2:3 and 4:6?

Back

The cross product is 2*6 and 3*4, both equal to 12, so they form a proportion.

Front

Solve for x: 4/5 = x/20

Back

x = 16.

Front

If a recipe requires 3 cups of flour for 4 servings, how much flour is needed for 10 servings?

Back

7.5 cups of flour.

Front

What is the formula to find a missing value in a proportion?

Back

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

Front

If 60% of a class passed a test and there are 30 students, how many passed?

Back

18 students passed.

Front

If 5 apples cost $2, how much do 15 apples cost?

Back

$6.