Percents in Everyday Life : Percents in Everyday Life
What is a percent? : What is a percent? A percent means “divided by 100”
It can be expressed using the symbol: %
A percent is equivalent to a fraction with a denominator of 100
Slide 3: What are some ways that you use percentages in your life?
Did you say: : Did you say: Shopping (discounts, tax) (see video)
Eating at a Restaurant (tipping, tax)
Calculating your grade in your classes Anything else?
How will you use percents when you are older? : How will you use percents when you are older? Paying taxes
Interest on a loan
Probability of an outcome
Calculating your body fat (see video) That is only a few…
How do percents relate to ratios? : How do percents relate to ratios? We use a formula to calculate percents by setting two ratios (or proportions) equal to each other:
Find a percent using a proportion : Find a percent using a proportion What percent of 25 is 17?
What percent of 25 is 17? : What percent of 25 is 17? Substitute the numbers in for the variables: Use cross products to rewrite: 17(100) = 25p
1700= 25p Divide each side by 25: 68 = p
What percent of 25 is 17? : What percent of 25 is 17? 17 is 68% of 25
The Percent Equation : The Percent Equation You can also use the percent equation to represent a is p percent of b:
Find a percent using the percent equation: : Find a percent using the percent equation: What percent of 136 is 51?
What percent of 136 is 51? : What percent of 136 is 51? Divide each side by 136: Write decimal as percent: 37.5% = p% Substitute the numbers in for the variables: 0.375 = p%
Now find other ways to use percentages : Now find other ways to use percentages Complete other exercises in your textbook using the two formulas just learned