Percents and Proportions

Front

What is a percent?

Back

A percent is a ratio expressed as a fraction of 100. It represents a part of a whole.

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 20% of 50, calculate 50 x 0.20 = 10.

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

How do you convert a fraction to a percent?

Back

To convert a fraction to a percent, divide the numerator by the denominator and multiply by 100. For example, 1/4 = (1 ÷ 4) x 100 = 25%.

Front

What is the formula for finding the percent increase?

Back

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

Front

What is the formula for finding the percent decrease?

Back

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

Front

If 30 is 1500% of what number, how do you find that number?

Back

To find the number, divide 30 by 1500% (or 15). So, 30 ÷ 15 = 2.

Front

How do you find the total when given a part and its percentage?

Back

To find the total, divide the part by the percentage (in decimal form). For example, if 25 is 20% of a total, then Total = 25 ÷ 0.20 = 125.

Front

What is the relationship between fractions, decimals, and percents?

Back

Fractions, decimals, and percents are different ways to represent the same value. For example, 1/2 = 0.5 = 50%.

Front

How do you compare two percentages?

Back

To compare two percentages, convert them to the same base (like decimals or fractions) and then compare the values.