Warm Up Problem of the Day Lesson Presentation Lesson Quizzes

Warm Up List the first five multiples of the following numbers. 1. 3 2. 12 3. 36 4. 48 3, 6, 9, 12, 15 12, 24, 36, 48, 60 36, 72, 108, 144, 180 48, 96, 144, 192, 240

Problem of the Day How much will it cost to build a fence that is 24 ft long, if it costs $20 to build a fence that is 15 ft long? $32

Learn to convert customary units of measure.

You can use the information in the table below to convert one customary unit to another. When you convert one unit of measure to another, you can multiply by a conversion factor.

Additional Example 1A: Using a Conversion Factor Convert 9 yards to feet. Set up a conversion factor. Think: yards to feet–3 feet = 1 yd, so use . 3 ft 1 yd 3 ft 1 yd Multiply using the conversion factor. Cancel the common unit, yd. 9 yd  9 yd = 27 ft Write the unit you are converting to in the numerator and the unit you are converting from in the denominator. Caution!

Additional Example 1B: Using a Conversion Factor Convert 10,000 pounds to tons. Set up a conversion factor. Think: pounds to tons–1 ton = 2,000 lbs, so use . 1 ton s 2,000 lbs Multiply 10,000 lbs by the conversion factor. Cancel the common unit, lbs. 1 ton 2,000 lb 10,000 lb  10,000 lb = 5 tons

Check It Out: Example 1A Convert 3 quarts to pints. Set up a conversion factor. Think: quarts to pints–2 pints = 1 quart, so use . 2 pt 1 qt 2 pt 1 qt 3 qt  Multiply using the conversion factor. Cancel the common unit, qt. 3 quarts = 6 pints

Check It Out: Example 1B Convert 15,840 feet to miles. Set up a conversion factor. Think: feet to miles–1 mile = 5,280 feet, so use . 1 mile 5,280 ft Multiply 15,840 ft by the conversion factor. Cancel the common unit, ft. 1 mi s 5,280 ft 15,840 ft  15,840 feet = 3 miles

Another way to convert units is to use proportions. Remember! A proportion shows that two ratios are equivalent. Use a conversion factor for one of the ratios.

Additional Example 2: Converting Units of Measure by Using Proportions Convert 3 quarts to cups. Convert quarts to cups. 3 qt = cups 1 quart is 4 cups. Write a proportion. Use a variable for the value you are trying to find. 1 qt 4 c 3 qt x = 1 • x = 4 • 3 The cross products are equal. 1x = 12 Divide both sides by 1 to undo the multiplication. x = 12 3 quarts = 12 cups.

Check It Out: Example 2 Convert 144 cups to gallons. Convert cups to gallons. 144 cups = gallons. 1 gallon is 16 cups. Write a proportion. Use a variable for the value you are trying to find. 1 gal 16 c x 144 c = 16 • x = 1 • 144 The cross products are equal. 16x = 144 Divide both sides by 16 to undo multiplication. x = 9 144 cups = 9 gallons.

Understand the Problem Additional Example 3: Problem Solving Application The football goal posts are 30 feet tall. How many inches is this? 1 Understand the Problem The answer will be the height of the goal posts in inches. List the important information: • The height of the goal posts are 30 feet tall.

Additional Example 3 Continued 2 Make a Plan Make a table from the information to show the number of inches in 1, 2, and 3 feet. Then find the number of inches in n feet.

Additional Example 3 Continued Solve 3 12n n 36 3 24 2 12 1 Inches Feet Look for a Pattern. 1 • 12 = 12 2 • 12 = 24 3 • 12 = 36 n • 12 = 12n 30 • 12 = 360 so, the goal posts are 360 inches tall.

Additional Example 3 Continued 4 Look Back Round 12 to 10. Then multiply by 30. 30 • 10 = 300 The answer is reasonable because 360 is close to 300.

Understand the Problem Check It Out: Example 3 The soccer field is 110 yards long. How many inches is this? 1 Understand the Problem The answer will be the length of the soccer field in inches. List the important information: • The soccer field is 110 yards long.

Check It Out: Example 3 Continued 2 Make a Plan Make a table from the information to show the number of inches in 1, 2, and 3 yard. Then find the number of inches in n yards.

Check It Out: Example 3 Continued Solve 3 36n n 108 3 72 2 36 1 Inches Yard Look for a Pattern. 1 • 36 = 36 2 • 36 = 72 3 • 36 = 108 n • 36 = 36n 110 • 36 = 3,960 so, the soccer field is 3,960 inches long.

Check It Out: Example 3 Continued 4 Look Back Round 110 to 100. Then multiply by 36. 36 • 100 = 3,600 The answer is reasonable because 3,960 is close to 3,600.

Lesson Quizzes Standard Lesson Quiz Lesson Quiz for Student Response Systems

Lesson Quiz 1. Convert 5 yards to inches. 2. Convert 16 tons to pounds. 3. Convert 11 quarts to cups. 4. A project requires 288 inches of tape. How many yards is this? 180 inches 32,000 pounds 44 cups 8 yards

Lesson Quiz for Student Response Systems 1. Which of the following represents 7 yards in inches? A. 252 in. B. 245 in. C. 238 in. D. 231 in.

Lesson Quiz for Student Response Systems 2. Which of the following represents 12 tons in pounds? A. 12,000 pounds B. 36,000 pounds C. 24,000 pounds D. 40,000 pounds

Lesson Quiz for Student Response Systems 3. Which of the following represents 14 quarts in cups? A. 196 cups B. 112 cups C. 84 cups D. 56 cups

Lesson Quiz for Student Response Systems 4. An electrician requires 324 inches of electrical wire. How many yards is this? A. 7 yards B. 8 yards C. 9 yards D. 10 yards