Percent 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 75% of 88, calculate 88 * 0.75 = 66.

Front

What is the formula to find what percent one number is of another?

Back

The formula is (part/whole) * 100. For example, to find what percent 12 is of 30, calculate (12/30) * 100 = 40%.

Front

If 25% of a quantity is known, how can you find the total quantity?

Back

To find the total quantity, divide the known quantity by the percentage (in decimal form). For example, if 12 is 25% of a quantity, the total quantity is 12 / 0.25 = 48.

Front

What does it mean if a number is increased by a certain percentage?

Back

Increasing a number by a percentage means adding that percentage of the number to itself. For example, increasing 100 by 20% means adding 20 (which is 20% of 100) to 100, resulting in 120.

Front

What does it mean if a number is decreased by a certain percentage?

Back

Decreasing a number by a percentage means subtracting that percentage of the number from itself. For example, decreasing 100 by 20% means subtracting 20 (which is 20% of 100) from 100, resulting in 80.

Front

How do you convert a fraction to a percentage?

Back

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

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 can you solve a proportion?

Back

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

Front

What is the relationship between percentages and fractions?

Back

Percentages can be expressed as fractions by placing the percentage over 100. For example, 50% = 50/100 = 1/2.