Fundamentals of Mathematics, 2008a

516 CHAPTER 9. MEASUREMENT AND GEOMETRY
this unit fraction has feet in the numerator. Now, multiply 11 yd by the unit fraction. Notice that
since the unit fraction has the value of 1, multiplying by it does not change the value of 11 yd.
11 yd = 11yd
1
· 3ft
1yd
= 11)yd 3ft
1
·
1)yd
11·3ft
=
1
= 33ft
Divide out common units.
(Units can be added, subtracted, multiplied, and divided, just as numbers can.)
Thus, 11 yd = 33ft.
Example 9.2
Convert 36 oz to pints.
Looking in the unit conversion table under liquid volume, we see that 1 pt = 16 oz. Since we
are to convert to pints, we will construct a unit fraction with pints in the numerator.
36 oz =
=
=
36 oz 1 pt
1
·
36) oz 1 pt
1
·
16) oz
36·1 pt
16
16 oz
Divide out common units.
36 pt
=
16
Reduce.
9
=
4 pt Convert to decimals: 9 4 = 2.25.
Thus, 36 oz = 2.25 pt.
Example 9.3
Convert 2,016 hr to weeks.
Looking in the unit conversion table under time, we see that 1wk = 7da and that 1 da = 24 hr.
To convert from hours to weeks, we must rst convert from hours to days and then from days to
weeks. We need two unit fractions.
The unit fraction needed for converting from hours to days is 1 da
24 hr
. The unit fraction needed for
converting from days to weeks is 1 wk
7 da .
2, 016 hr =
=
=
2,016 hr
1
· 1 da
24 hr · 1 wk
2,016) hr 1) da
1
· · 1 wk
24) hr 7) da
2,016·1wk
24·7
Reduce.
= 12wk
Thus, 2,016 hr = 12 wk.
7 da
Divide out common units.
9.2.4.2 Practice Set A
Make the following conversions. If a fraction occurs, convert it to a decimal rounded to two decimal places.
Exercise 9.2.1 (Solution on p. 569.)
Convert 18 ft to yards.
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