A ratio is a way to describe a relationship between two numbers. There are three ways to write a ratio. Example: There are 12 boys in the class and 15 girls. What is the ratio of boys to girls? Solution: We must give the numbers in the order that the question asks. The boy number must be given first then the girl number. You may or may not need to reduce.
Proportions are two equivalent ratios. Refer back to the Proportion, Ratio and Rates Lesson for examples.
Lastly, percents can also be tied into ratios and proportions. Example: The ratio of salmon to walleye is 7 to 3. What is the percent of salmon? Solution: We can find that the total ratio of fish is 10. To find the percent of salmon we would set up a proportion with 100 as the denominator of the second fraction. We use 100 because all percents are out of 100. We then solve for the variable.
The percent of salmon is 70%.
