Using Proportions for Percent Problems

Front

What is a proportion?

Back

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

Front

How do you find the percent of a number?

Back

To find the percent of a number, multiply the number by the percent (as a decimal). For example, to find 20% of 50, calculate 50 x 0.20 = 10.

Front

What is the formula to find the percent?

Back

The formula to find the percent is: Percent = (Part/Whole) x 100.

Front

If 15 is 10% of a number, how do you find that number?

Back

To find the number, divide the part (15) by the percent (0.10). So, 15 ÷ 0.10 = 150.

Front

What is 22% of 300?

Back

22% of 300 is 66.

Front

How do you calculate the total number of students if 75% of them buy lunch?

Back

If 75% of students buy lunch, you can find the total by dividing the number of students who buy lunch by 0.75. For example, if 45 students buy lunch, then Total = 45 ÷ 0.75 = 60.

Front

What percent of 300 is 246?

Back

To find what percent 246 is of 300, use the formula: Percent = (246/300) x 100 = 82%.

Front

If 36 is 60% of a number, how do you find that number?

Back

To find the number, divide 36 by 0.60. So, 36 ÷ 0.60 = 60.

Front

What is the relationship between fractions and percentages?

Back

Fractions can be converted to percentages by multiplying the fraction by 100. For example, 1/4 = 0.25 x 100 = 25%.

Front

How do you express a percentage as a decimal?

Back

To express a percentage as a decimal, divide by 100. For example, 25% = 25 ÷ 100 = 0.25.