ratios and proportions

Front

What is a ratio?

Back

A ratio is a comparison of two quantities by division, showing how many times one value contains or is contained within the other.

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 3 apples cost $1.50, how much do 12 apples cost?

Back

$6.00

Front

What is the ratio of 4 red marbles to 6 blue marbles?

Back

2 to 3

Front

If a recipe requires 2 cups of sugar for 5 servings, how much sugar is needed for 20 servings?

Back

8 cups of sugar

Front

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

Back

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

Front

If 8 pencils cost $4, how much do 20 pencils cost?

Back

$10

Front

What is the relationship between ratios and fractions?

Back

Ratios can be expressed as fractions, where the first quantity is the numerator and the second quantity is the denominator.

Front

If the ratio of boys to girls in a class is 3 to 4, how many boys are there if there are 28 girls?

Back

21 boys.