Basic Mathematics for College Students

Define American units of weight.

The American system of measurement uses the units ofounce, pound,and ton to
measure weight. These units are related in the following ways.

American Units of Weight

1 pound (lb) 16 ounces (oz) 1 ton (T)2,000 pounds

The abbreviation for each unit is written within parentheses.

Convert from one American unit of weight to another.

To convert units of weight in the American system of measurement, we use the
following unit conversion factors. Each conversion factor shown below is a form of 1.

5

4

5.3 American Units of Measurement 447

StrategyWe will use a two-part multiplication process that converts 120 yards to
feet and then converts that result to miles.

WHYWe must use a two-part process because the table on page 445 does not
contain a single unit conversion factor that converts from yards to miles.

Solution
Since there are 3 feet per yard, we can convert 120 yards to feet by multiplying by
the unit conversion factor. Since there is 1 mile for every 5,280 feet, we can
convert that result to miles by multiplying by the unit conversion factor.

Write 120 yd as a fraction: 120 yd 

Then multiply by two unit conversion

factors: and.

Multiply the fractions.

A football field (including the end zones) is exactly miles long.
We can also present this conversion as a decimal. If we divide
3 by 44 (as shown on the right), and round the result to the nearest
hundredth, we see that a football field (including the end zones) is
approximately0.07 mile long.

3

44

Multiply the remaining

factors in the numerator.

Multiply the remaining

factors in the denominator.



3

44

mi

To simplify the fraction, prime factor

120 and 5,280, and remove the common

factors 2, 3, and 5.



2

1

 2

1

 2

1

 3

1

 5

1

 3

2

1

 2

1

 2

1

 2  2  3

1

 5

1

 11

mi



120 # 3

5,280

mi

Remove the common units of yards and

feet in the numerator and denominator.

Notice that all the units are removed

except for miles.



120 yd

1



3 ft

1 yd



1 mi

5,280 ft

1 mi

5,280 ft^1

3 ft

1 yd^1

120 yd

1

120 yd

120 yd

1



3 ft

1 yd



1 mi

5,280 ft

1 mi

5,280^ ft^

3ft

1yd^

0.068

(^44) 3.000
 0
300
 264
360
 352
8
Use the unit Use the unit
To convert conversion To convert conversion
from factor from factor
pounds to ounces ounces to pounds
tons to pounds 2,000 lb1 ton pounds to tons 2,000 lb1 ton
1 lb
16 oz
16 oz
1 lb