Ratios and Proportions

Front

What is a ratio?

Back

A ratio is a comparison of two quantities, 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 calculate a percentage of a number?

Back

To calculate a percentage of a number, multiply the number by the percentage (in decimal form). For example, 15% of 60 is 60 * 0.15 = 9.

Front

What is the formula to find the discount amount?

Back

Discount Amount = Original Price × Discount Rate.

Front

If Paul saves 40% on a $20 shirt, how much does he save?

Back

Paul saves $8.

Front

What is the value of x in the equation 2x + 4 = 36?

Back

x = 16.

Front

How do you solve a proportion?

Back

Cross-multiply the two ratios and set them equal to each other. For example, if a/b = c/d, then ad = bc.

Front

What is 15% of 60?

Back

15% of 60 is 9.

Front

If 3/4 of a number is 12, what is the number?

Back

The number is 16.

Front

What does it mean if two ratios are equivalent?

Back

It means that they represent the same relationship between quantities.