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COURSE 3 LESSON 5-2 Choosing and Converting Units Use dimensional analysis to convert 0.7 mi to ft. 0.7 mi = = 0.7 mi 5,280 ft • 1 1 mi Multiply by a conversion factor. Divide by the common units. (0.7)(5,280) ft 1 Simplify. Simplify. = 3,696 ft There are 3,696 ft in 0.7 miles. 5-2 COURSE 3 LESSON 5-2 Choosing and Converting Units A rowing team completed a 2,000-m course at a rate of 6.84 m/s. Convert this rate to kilometers per minute. Estimate 6.84 7. Then, 7 • 60 ÷ 1000 = 0.42. 6.84 m 6.84 m 1 km = • • 1s 1s 1000 m 60 s 1 min (6.48)(1)(60) km Multiply by two ratios that each equal one. Divide by the common units. = (1)(1,000)(1) min Simplify. = 0.4104 Use a calculator. The team rowed at a rate of 0.4104 km/min. Check for Reasonableness The answer 0.4104 km/min is close to the estimate 0.42. The answer is reasonable. 5-2 COURSE 3 LESSON 5-2 Choosing and Converting Units Use compatible numbers to estimate the number of gallons in 33 quarts. 1 gal The conversion factor for changing gallons to quarts is 4 qt . Round to the nearest number 33 qt 32 qt divisible by 4. = 32 qt 1 gal • 1 4 qt Multiply by the conversion factor. Divide by the common units. 32 = 4 gallons Simplify. = 8 gallons Divide. There are about 8 gallons in 33 quarts. 5-2 COURSE 3 LESSON 5-2 Choosing and Converting Units 1. Choose an appropriate customary unit and metric unit for the distance between two cities. miles; kilometers 2. Convert 0.75 hours to seconds. 2,700 s 3. $150 per hour is how much per minute? $2.50 per min 4. 69.2 cm is about how many meters? 0.7 m 5-2