Ratios and Proportions

Chapter 5 Ratio and Proportion reviews how numbers are related to one another through comparisons. 

Chapter 6 Percent covers the most common use of ratio and proportion on tests and in daily life. 

Ratios are numbers that are used to compare things. Ratios play an important role in mathematics because they quantify all of the items that we compare on a day-to-day basis. Ratio and proportion are evident in numerous mathematical problems. Before you begin learning about ratios and proportions, take a few minutes to take this ten-question Benchmark Quiz. These questions are similar to the type of questions that you will find on important tests. When you are finished, check the answer key carefully to assess your results. Your Benchmark Quiz analysis will help you determine how much time you need to spend on ratios and proportions, and the specific areas in which you need the most careful review and practice. 

How did you do on the ratio and proportion Benchmark Quiz Check your answers here, and then analyze your results to figure out your plan of attack to master these topics. 

If you answered 8-10 questions correctly, you have a good understanding of ratio and proportion. After reading through the lesson and focusing on the areas you need to refresh, try the quiz at the end of the chapter to ensure that all of the concepts are clear. 

This lesson covers the basics of working with ratio and proportions. The topics in this chapter are ... 

To solve problems involving ratios and proportions, you can use the method of cross-multiplication. 

For further practice and extended lessons on ratio and proportions, refer to Practical Math Success in 20 Minutes a Day, Lesson 12, Ratio and Proportion. In addition, the website www.math.com has helpful mini lessons and further practice problems. Click on Pre-Algebra from the column entitled Select Subject. Then click on any of the following links, under the title Ratios and Proportions Ratios, Proportions, Distance, Rates and Time, or Similar Figures. 

Now that you have studied these lessons, see how much you have learned and reviewed about ratio and proportion. 

Throughout the course of this book, we have looked at many word problems. Several problems involving distance and speed, percents, simple interest, and ratio and proportions have been reviewed. One other type of word problem not reviewed previously is consecutive integer problems. These problems are relatively easy to solve on multiple-choice tests. 

We are now ready to set up a ratio and proportion (2 fractions equal to each other) and solve for W. 

Once we have the values, we set up the ratio and proportion, then solve for t. This time, we decided to cancel out like units as we brought them down from the equation to the ratio and proportion (shortcut). 

We use the information associated with the balanced equation to set up the ratio and proportion. Again, we need to watch to see if the desired unit appears in the solution. 

Canceling similar units as the values are brought from the equation to the ratio and proportion gives us 333.3 424.6 g K3P04, 5.00 x 424.6 K3PQ4... 

From this setup, we can write the ratio of the mole-related information to the mass in the problem for both sides of the equation and relate them to each other (ratio and proportion). Notice that we have canceled moles against moles when we brought the ratios from above to below. 

Another setup for the problem takes advantage of the ratio and proportion (w is the mass desired) ... 

Complex fractions may not be so common, but ratios and proportions can be used to help us solve everyday problems. Now that you are a fractions expert, it s time to learn about decimals. 

Several methods the epidemiologist has for investigating relationships vary greatly in cost, time and energy expended, and analytic and interpretive value. The descriptive study is simply, as the name implies, a series of rates, ratios, and proportions which help describe either the exposure or the outcome in detail. The case-control study is relatively easy to carry out, and new analytic techniques have already increased its interpretive value. An exposure study, although not strictly in the realm of epidemiology, documents exposure in various substrata of a population. 

Execution knowledge. The execution knowledge most closely associated with the Vary schema is knowledge about multiplication and division, about ratios and proportions, and about rates. As before, it also entails searching for the unknowns. 

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