7.1 Basic Terms and Conversions Within the Metric System 415 Example 3 Running Races Running race distances are often given in kilometers. The following table gives the distances of popular races in kilometers. Race Distance in Kilometers 5K 5 10K 10 10-Miler 16.093 4 Half-Marathon 21.082 4 Marathon 42.164 8 David, an avid runner, has run 3 marathons, 7 half-marathons, 12 10-milers, 23 10Ks, and 51 5Ks. a) Determine the total distance, in kilometers, that David has run during these races. b) Determine the total distance, in meters, that David has run during these races. Solution a) We begin by multiplying the number of each type of race David ran by the distance, in kilometers, of the race. The total distance is the sum of these products. Total Distance 3(42.1648) 7(21.0824) 12(16.0934) 23(10) 51(5) 126.4944 147.5768 193.1208 230 255 952.192 = + + + + = + + + + = Thus, the total distance David ran in these races is 952.192 km b) To convert the total distance David ran into meters, we move the decimal point 3 places to the right. Thus, the total distance David ran in these races is 952 192 m. 7 Now try Exercise 59 Example 4 Comparing Lengths Arrange in order from smallest to largest length: 2.3 m, 3421 mm, and 104 cm. Solution To be compared, these lengths should all be in the same units of measure. Let’s convert all the measures to millimeters, the smallest units of the lengths being compared. 2.3 m 2300 mm 3421 mm 104 cm 1040 mm = = Since the lengths, in millimeters, from smallest to largest are 1040, 2300, 3421, the lengths arranged in order from smallest to largest are 104 cm, 2.3 m, and 3421 mm. 7 Now try Exercise 43 Learning Catalytics Keyword: Angel-SOM-7.1 (See Preface for additional details.) TECHNOLOGY TIP Metric System Apps There are several apps available for use on most smartphones and tablets that can assist in the conversion between the U.S. customary system and the metric system. These apps are particularly helpful when traveling outside of the United States to countries that use the metric system. These apps can also be used to check your work throughout this chapter. In addition to these apps, several websites including, Metric-Conversions.org and NIST.gov, provide useful information about the metric system. As always, check with your instructor prior to using any apps or websites to complete required work for your course. Instructor Resources for Section 7.1 in MyLab Math • Objective-Level Videos 7.1 • Animation: Metric System Conversions • PowerPoint Lecture Slides 7.1 • MyLab Exercises and Assignments 7.1 Wavebreakmedia/Shutterstock
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