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

How do you simplify a ratio?

Back

To simplify a ratio, divide both terms by their greatest common divisor (GCD).

Front

What is a proportion?

Back

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

Front

How can you determine if two ratios form a proportion?

Back

Cross-multiply the ratios. If the products are equal, the ratios form a proportion.

Front

What is the ratio of girls to boys in a class with 16 boys and 32 girls?

Back

Front

If Gracie has 24 cookies for 3 classes, how many cookies per class does she have?

Back

Gracie has 8 cookies per class (24 cookies ÷ 3 classes).

Front

If Gracie has 4 classes tomorrow, how many cookies should she bring?

Back

Gracie should bring 32 cookies (8 cookies per class × 4 classes).

Front

What is the cost per pound of a 20-lb bag of dog food that costs $23.44?

Back

The cost per pound is approximately $1.17 ($23.44 ÷ 20 lbs).

Front

What is the cost per pound of an 8-lb bag of dog food that costs $9.88?

Back

The cost per pound is approximately $1.24 ($9.88 ÷ 8 lbs).

Front

What is the cost per pound of a 40-lb bag of dog food that costs $49.00?

Back

The cost per pound is $1.23 ($49.00 ÷ 40 lbs).