Math 015 Section 8.1 Percents

Obj: To write a percent as a fraction or a decimal Percent means parts of 100 In the figure at the right, 23 of the 100 squares are shaded. We say that 23% of the squares are shaded. In most application problems it will be necessary to convert percents to fractions or decimals in order to work with them in the problems.

Obj: To write a percent as a fraction or a decimal 1. remove the percent sign 2. divide by 100 3. simplify the fraction Examples: change the following percents to fractions 13 13 100 13% = = 100 44 11 25 44% = = 100

Obj: To write a percent as a fraction or a decimal 1. remove the percent sign 2. divide by 100 3. simplify the fraction Examples: change the following percents to fractions 240 12 25 240% = = = 2 100 5 1 23 16 1 100 23 = 50 16 16 % = · = 3 100 2

Certain percents and their fraction equivalents should be memorized 1 5 20 % 25 % 50 % 75 % = 1 6 23 16 % 33 % 66 % = 1 4 1 3 13 1 2 2 3 23 3 4

Obj: To write a percent as a fraction or a decimal To write a percent as a decimal 1. remove the percent sign 2. divide by 100 Examples: change the following percents to decimals 61 % = 61 ¸ 100 = 0.61 0.5 % = 0.5 ¸ 100 = 0.005 235 % = 235 ¸ 100 = 2.35

Obj: To write a fraction or a decimal as a percent To write a fraction or decimal as a percent 1. multiply by 100 % Examples: change the following to percents 38 38 100 % 300 75 12 = · = % = % = 37 % 8 2 0.048 = 0.048 · 100 % = 4.8 % 1.17 = 1.17 · 100 % = 117 %

1 Obj: To write a fraction or a decimal as a percent To write a fraction or decimal as a percent 1. multiply by 100 % Write as a percent: write the remainder in fraction form 56 56 100 % 500 250 % 13 = · = % = = 83 % 6 3 Write as a percent: round to the nearest tenth 13 100 % 1300 1 49 = · = % = 144.4 % 9 9