6.1 Understand percent

Use the definition of percent

How many cents are in one dollar? There are $100$ cents in a dollar. How many years are in a century? There are $100$ years in a century. Does this give you a clue about what the word “percent” means? It is really two words, “per cent,” and means per one hundred. A percent    is a ratio whose denominator is $100.$ We use the percent symbol $\text{\%,}$ to show percent.

According to data from the American Association of Community Colleges $(2015)\text{,}$ about $\text{57\%}$ of community college students are female. This means $57$ out of every $100$ community college students are female, as [link] shows. Out of the $100$ squares on the grid, $57$ are shaded, which we write as the ratio $\frac{57}{100}.$

Similarly, $\text{25\%}$ means a ratio of $\frac{25}{100},\text{3\%}$ means a ratio of $\frac{3}{100}$ and $\text{100\%}$ means a ratio of $\frac{100}{100}.$ In words, "one hundred percent" means the total $\text{-100\%-}$ is $\frac{100}{100},$ and since $\frac{100}{100}=1,$ we see that $\text{100\%}$ means $1$ whole.

Convert percents to fractions and decimals

Since percents are ratios, they can easily be expressed as fractions. Remember that percent    means per $100,$ so the denominator of the fraction is $100.$