1 Learn U.S. Customary Measurements We use measurements every day: inches to measure the diagonal of a television screen, miles to measure the distance between two cities, quarts or gallons to measure a quantity of milk, pounds to measure our weight, and so on. Each of these is an example of a U.S. customary measurement unit. In the United States, we use U.S. customary units while most of the rest of the world uses the metric system. (The metric system uses units such as meters, liters, and grams. We will study the metric system in future sections.) In both systems, time is measured with the same units: seconds, minutes, hours, days, etc. Sometimes, we must convert between different units like yards and feet. Therefore, we need to memorize the relationships between the units and their abbreviations given in the table here. Relationships Between U.S. Customary Measurements Length Time 12 inches (in.) 1 foot (ft) 60 seconds (sec) 1 minute (min) 3 feet (ft) 1 yard (yd) 60 minutes (min) 1 hour (hr) 5280 feet (ft) 1 mile (mi) 24 hours (hr) 1 day 7 days 1 week (wk) Capacity Weight 8 fl uid ounces (fl oz) 1 cup (c) 16 ounces (oz) 1 pound (lb) 2 cups (c) 1 pint (pt) 2000 pounds (lb) 1 ton 2 pints (pt) 1 quart (qt) 4 quarts (qt) 1 gallon (gal) Let’s practice using these basic relationships. Fill in the blank. a) 1 ft in. 1 ft 12 in. b) wk 1 yr 52 wk 1 yr c) 1 gal qt 1 gal 4 qt EXAMPLE 1 YOU TRY 1 Fill in the blank. a) 1 yd ft b) lb 1 ton c) c 1 pt Very often we have to convert between the units given in the table. A recipe, for example, might call for 2 1 2 cups of milk, but at the grocery store we buy milk in pints, quarts, or gallons. Do we buy a pint, a quart, or a gallon? Let’s learn how to change from one U.S. unit to another. We can do this in two different ways: using multiplication or division, or using unit analysis. www.mhhe.com/messersmith SECTION 7.1 Using U.S. Customary Measurements 567
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