Page 442 - Basic College Mathematics with Early Integers

S E C T I O N 5.7 I CONVERSIONS BETWEEN THE U.S. AND METRIC SYSTEMS 419

Thus, the diameter of a standard compact disc is exactly 12 cm or approximately
4.72 inches. For a dimension this size, you can use a ruler to check. Another
method is to approximate. Our result, 4.72 in., is close to 5 inches. Since 1 in. is
about 2.5 cm, then 5 in. is about 5(2.5 cm) = 12.5 cm, which is close to 12 cm.
Work Practice 1

Example 2 Liver PRACTICE 2
A full-grown human heart
The liver is your largest internal organ. It weighs about 3.5 pounds in a grown
weighs about 8 ounces. Convert
man. Convert this weight to kilograms. Round to the nearest tenth. (Source: Some
this weight to grams. If neces-
Body! by Dr. Pete Rowan)
sary, round your result to the
Unit fraction
nearest tenth of a gram.
L
3.5 lb 0.45 kg
Solution: 3.5 lb L # = 3.5(0.45 kg) L 1.6 kg
1 1lb
Thus 3.5 pounds are approximately 1.6 kilograms. From the table of conversions,
we know that 1 kg L 2.2 lb. So that means 0.5 kg L 1.1 lb and after adding, we
have 1.5 kg L 3.3 lb. Our result is reasonable.

Work Practice 2

Example 3 Postage Stamp PRACTICE 3
Australia converted to the metric system in 1973. In Convert 237 ml to fluid ounces.
that year, four postage stamps were issued to publi- Round to the nearest whole
cize this conversion. One such stamp is shown. Let’s fluid ounce.
check the mathematics on the stamp by converting
7 fluid ounces to milliliters. Round to the nearest
hundred.
Unit fraction
L
7 fl oz 29.57 ml
Solution: 7 fl oz L # = 7(29.57 ml) = 206.99 ml
1 1 fl oz
Rounded to the nearest hundred, 7 fl oz L 200 ml.
Work Practice 3

Answers
2. 226.8 g 3. 8 fl oz