Proportions and Percents

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. For example, if a/b = c/d, then a, b, c, and d are in proportion.

Front

What is a percent?

Back

A percent is a ratio expressed as a fraction of 100. It is often used to compare quantities.

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, to find 25% of 200, calculate 200 * 0.25 = 50.

Front

What is the formula for finding the percent of a number?

Back

The formula is: Percent = (Part/Whole) * 100.

Front

How do you convert a fraction to a percent?

Back

To convert a fraction to a percent, divide the numerator by the denominator and then multiply by 100. For example, 1/4 = 0.25 * 100 = 25%.

Front

What is the relationship between proportions and ratios?

Back

A ratio is a comparison of two quantities, while a proportion states that two ratios are equal. For example, if 1:2 = 2:4, then these ratios are in proportion.

Front

How do you solve a proportion?

Back

To solve a proportion, cross-multiply and then divide. For example, if a/b = c/d, then ad = bc.

Front

What is the percent increase formula?

Back

Percent Increase = ((New Value - Original Value) / Original Value) * 100.

Front

What is the percent decrease formula?

Back

Percent Decrease = ((Original Value - New Value) / Original Value) * 100.

Front

If 30% of a number is 60, what is the number?

Back

To find the number, divide 60 by 0.30. The number is 200.