3CaliforniaStandardsAF2.1 Convert one unit of measurement to another (e.g., from feet to miles, from centimeters to inches).Also covered: NS1.3
4Objective: You will learn how to identify and compare customary units of measurement.
5You can use the following benchmarks to help you understand fluid ounces, tons, and other customary units of measure.
6Example 1: Choosing the Appropriate Customary Unit Choose the most appropriate customary unit for each measurement. Justify your answer.A. the weight of a cartons; The weight of a car is similar to the weight of a buffalo.B. the diameter of a soap caninches; The diameter of a soup can is similar to the length of a few paper clips.C. the weight of a newborn babypounds; The weight of a newborn baby is similar to the weight of more than a dozen apples.
7Check It Out! Example 2Choose the most appropriate customary unit for each measurement. Justify your answer.A. the length of a pen topinch; The length of a pen top is similar to the length of a small paper clip.B. the weight of a pitcher of juicepounds; The weight of a pitcher of juice is similar to the weight of about 10 apples.C. the capacity of a jar of peanut buttercups; The capacity of a jar of peanut butter is similar to the capacity of 2 standard measuring cups.
9Example 3: Converting Customary Units Convert 5,000 pounds to tons.Method 1: Use a Proportion.Write a proportion using a ratio of equivalent measures.pounds tons2,000 15,000 m x=2,000 • x = 1 • 5,0002,000x = 5,000x = 2.55,000 pounds is equal to 2.5 tons.
10Example 3 ContinuedConvert 5,000 pounds to tons.Method 2: Multiply by 1.Multiply by a ratio equal to 1, and cancel the units.5,000 lb m 11 ton t 2,000 lb5,000 lb = 1 ton t 2,000= 5,000 = 2.5 tons5,000 pounds is equal to 2.5 tons.
11Check It Out! Example 4Convert 24 pints to cups.Method 1: Use a Proportion.Write a proportion using a ratio of equivalent measures.cups pints2 1c 24=1 • c = 2 • 24c = 4824 pints is equal to 48 cups.
12Check It Out! Example 4 Continued Convert 24 pints to cups.Method 2: Multiply by 1.Multiply by a ratio equal to 1, and cancel the units.24 pt m12 ct 1 pt24 pt = 2 c 1= 24 = 48 cups24 pints is equal to 48 cups.
13Example 5: Converting Between Metric and Customary Units One mile is about 1.6 kilometers. What is the length in miles of a 10 kilometer race? Round to the nearest tenth of a mile.miles kilometersx 10Write a proportion using mile 1.6 kilometers.=1.6 · x = 1 · 10The cross products are equal.1.6x = 10Multiply.1.6x1.6101.6=Divide each side by 1.6.x 6.3Round to the nearest whole number.The length of a 10 kilometer race is about 6.3 miles long.
14Check It Out! Example 6One cup is about 8 fluid ounces. What is the amount in cups of a 35 fluid ounce container? Round to the nearest tenth of a cup.cups fluid ounces1 8x 35Write a proportion using cup = 8 fluid ounces.=8 · x = 1 · 35The cross products are equal.8x = 35Multiply.8x8358=Divide each side by 8.x 4.4Round to the nearest whole number.The amount of a 35 fluid ounce container is about 4.4 cups.
16Lesson Quiz: Part IChoose the most appropriate customary unit for each measurement. Justify your answer.1. the capacity of a bathtub2. the weight of a calculator3. the length of an indoor sports arenagallons; similar to the capacity of several large milk jugsounces; similar to the weight of several slices of breadtoo small to measure in miles, so it should be measured in feet
17Lesson Quiz: Part II4. Convert 13 gallons to quarts.5. One ounce is about 28.3 grams. A box of cereal has a mass of 400 grams. What is the weight of the box in ounces? Round to the nearest tenth of an ounce.5214.1 oz