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U.S. customary system, p. 230 length: inch, foot, yard, mile, p. 230 weight: ounce, pound, ton, p. 231 capacity: fluid ounce, cup, pint, quart, gallon, p. 232
B E F O R E
You measured and estimated using metric units.
Now
You’ll measure and estimate using customary units.
W H Y ?
So you can estimate the weight of an elephant, as in Ex. 22.
The units of measurement for length, weight, and capacity commonly used in the United States are part of the U.S. customary system .
Length The inch (in.) is a unit of length in the customary system.
Three other customary units of length are the foot (ft) , yard (yd) , and mile (mi) . You can use the following benchmarks to estimate length.
1 inch length of a small paper clip
1 foot distance from shoulder to elbow
1 yard width of a door
1 mile combined length of 15 football fields
E X A M P L E
1
To estimate the length of a barrette, think of small paper clips laid next to it. Then measure the barrette with a ruler to check your estimate.
About 1
1
2 paper clips fit alongside the barrette, so it is about 1
1
2 inches long.
The ruler shows sixteenths of an inch, so the barrette is
1
1 4
1 6
, or 1
7
8
, inches long.
230 Chapter 5 Fraction Operations

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Be careful to distinguish between mass and weight.
Your mass is the same wherever you are, but your weight depends on gravity.
On the moon, for instance, you would weigh about
1
6 of what you weigh on
Earth.
Weight The weight of an object tells you how heavy the object is. Three customary units of weight are the ounce (oz) , pound (lb) , and ton (T) . You can measure the weight of an object using a scale.
E X A M P L E 2
Find the weight of the bananas.
Each pound is divided into sixteenths, so the arrow is at the 1
1 4
1 6 lb or 1
7
8 lb mark.
ANSWER The bananas weigh 1
7
8 pounds.
8 lb
9 lb
0 lb
1 lb
2 lb
7 lb
6 lb
5 lb
4 lb
3 lb b
0 lb
1 lb
2 lb
3 lb
You can use the following benchmarks to estimate weight.
1 ounce slice of bread
1 pound soccer ball
1 ton walrus
E X A M P L E
3
Copy and complete the statement using the appropriate customary unit: The weight of a bowling ball is 14 _?_.
The weight of a bowling ball is greater than the weight of 14 slices of bread (14 oz), and it is certainly less than the weight of 14 walruses
(14 T). Because a good estimate for the weight of a bowling ball is the weight of 14 soccer balls, the appropriate customary unit is pounds.
ANSWER The weight of a bowling ball is 14 pounds.
Y our turn now Complete the following exercises.
1.
Estimate the length of an unsharpened pencil in inches. Then use a ruler to check your estimate.
2.
The weight of a baseball bat is 33 _?_.
Lesson 5.5 Measuring in Customary Units 231

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W a t
A fluid ounce is not the same as an ounce.
Fluid ounces are a measure of the capacity of a container holding liquid, while an ounce measures the weight of the container.
Capacity Capacity is a measure of the amount that a container can hold. Five customary units of capacity are the fluid ounce (fl oz) , cup (c) pint (pt) quart (qt) gallon (gal) .
E X A M P L E
4
Find the amount of liquid in the measuring cup.
Each cup is divided into fourths, so the liquid is at the 3
3
4 cup level.
ANSWER There are about 3
3
4 cups of liquid in the measuring cup.
You can use the benchmarks shown to estimate capacity.
1 fluid ounce
E X A M P L E
5
What is the most reasonable capacity of a lemonade pitcher?
A.
8 fl oz B.
2 qt C.
10 gal D.
3 c
Solution
Both 8 fluid ounces and 3 cups of water are too little to fill the pitcher.
A pitcher couldn’t hold more than a gallon, so 10 gallons is too much.
That leaves 2 quarts of water, which seems an appropriate capacity.
ANSWER The most reasonable capacity of a lemonade pitcher is (B) 2 qt.
Y our turn now
3.
Juice glass
Match the object with the appropriate capacity.
4.
Paint can 5.
Ice cube tray
A.
1 gal B.
1 pt C.
7 fl oz
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1.
Vocabulary Which unit measures capacity: yard , cup , or pound ?
Copy and complete using the appropriate customary unit.
2.
A dictionary is 2
1
2
_?_ thick.
3.
A marathon is 26
1
5
_?_ long.
4.
A stapler weighs 8 _?_.
5.
A swimming pool holds 15,000 _?_.
6.
Sunglasses Dave thinks that the weight of a pair of sunglasses is 7 oz.
Mary thinks that the weight is about 2 lb. Who is right? Explain.
with
Example Exercises
3
4
1
2
5
7–9, 14–17, 21–22
10–11
14–17, 21–22
12–13
14–17
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• More Examples
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Estimate the length of the object in inches. Then measure the object using a ruler.
7.
Your shoe 8.
Calendar 9.
Picture frame
Find the weight of the object.
10.
11.
8 lb
9 lb
7 lb
6 lb
5 lb
4 lb
8 lb
9 lb
7 lb
6 lb
Find the amount of liquid in the measuring cup.
12.
13.
0 lb
1 lb
Copy and complete using the appropriate customary unit.
14.
Mount Everest is 5
1
2
_?_ high.
15.
A tennis racket weighs 20
16.
A shampoo bottle holds 12 _?_.
17.
A teakettle holds 5 _?_ .
1
2
_?_ .
Tell what measurement tool would be appropriate for the given unit.
18.
fluid ounce 19.
inch 20.
pound
Lesson 5.5 Measuring in Customary Units 233

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In Exercises 21 and 22, choose the letter of the most reasonable measurement.
21.
Travel What is the distance between Austin, Texas, and
Tallahassee, Florida?
A.
1760 yd B.
7000 ft C.
600 in.
D.
800 mi
22.
Elephants What is the weight of an Indian bull elephant?
F.
3
1
2
T G.
600 lb H.
2000 oz I.
100 lb
23.
Critical Thinking If one scale has each pound divided into fourths and another scale has each pound divided into halves, which scale will give you a more precise measurement? Explain your reasoning.
Tell whether an exact answer or an estimate is needed for the given situation.
24.
Sawing wood to build a deck 25.
Distance from home to the park
26.
The amount of weight you lost 27.
Your finish time in a track race
28.
Challenge Is it possible for two containers, when filled, to have the same weight but different capacities? If so, give an example. If not, explain why not.
■ Elephants
An Indian bull elephant’s footprint has a width of about 1
1
2 feet. How many of your footprints would fit across the footprint of an
Indian bull elephant?
Choose a Strategy Use a strategy from the list to solve the following problem.
Explain your choice of strategy.
29.
Jackie, Sean, Tim, and Katie have four seats in a row at a basketball game.
In how many different ways can they sit?
Problem Solving Strategies
■
Make a List
■
Estimate
■
Look for a Pattern
Copy and complete the statement.
30.
120 min _?_ h 31.
90 sec _?_ min 32.
3 wk _?_ d
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33.
Multiple Choice What is a reasonable capacity for a fish aquarium?
A.
18 fl oz B.
7 pt C.
16 qt D.
14 gal
34.
Multiple Choice Which is the greatest length?
F.
30 in.
G.
3 ft H.
1
2 mi I.
1 yd
234 Chapter 5 Fraction Operations