Page 441 - Basic College Mathematics with Early Integers

Objective 5.7 CONVERSIONS BETWEEN THE U.S. AND METRIC SYSTEMS

Convert Between the U.S.
and Metric Systems.
Objective Converting Between the U.S. and Metric Systems
The metric system probably had its beginnings in France in the 1600s, but it was the
Metric Act of 1866 that made the use of this system legal (but not mandatory) in the
United States. Other laws have followed that allow for a slow, but deliberate, trans-
fer to the modernized metric system. In April 2001, for example, the U.S. Stock
Exchanges completed their change to decimal trading instead of fractions. By the
end of 2009, all products sold in Europe (with some exceptions) were required to
have only metric units on their labels. (Source: U.S. Metric Association and National
Institute of Standards and Technology)
You may be surprised at the number of everyday items we use that are already
manufactured in metric units. We easily recognize 1L and 2L soda bottles, but what
about the following?

Pencil leads (0.5 mm or 0.7 mm)
Camera film (35 mm)
Sporting events (5-km or 10-km races)
Medicines (500-mg capsules)
Labels on retail goods (dual-labeled since 1994)
Since the United States has not completely converted to the metric system, we
1 yard
need to practice converting from one system to the other. Below is a table of mostly
Length
approximate conversions.
1 meter
Length: Capacity: Weight (mass):
Metric U.S. System Metric U.S. System Metric U.S. System
Capacity 1 m L 1.09 yd 1 L L 1.06 qt 1 kg L 2.20 lb
1 m L 3.28 ft 1 L L 0.26 gal 1 g L 0.04 oz
1 km L 0.62 mi 3.79 L L 1 gal 0.45 kg L 1 lb
1 quart 1 liter 2.54 cm = 1 in. 0.95 L L 1 qt 28.35 g L 1 oz
1 pound 1 kilogram 0.30 m L 1 ft 29.57 ml L 1 fl oz
1.61 km L 1 mi

Weight (Mass) There are many ways to perform these metric-to-U.S. conversions.We will do so
by using unit fractions.

PRACTICE 1 Example 1 Compact Discs
The center hole of a standard-
Standard-sized compact discs are 12 centimeters in diameter. Convert this length
sized compact disc is
to inches. Round the result to two decimal places. (Source: usByte.com)
1.5 centimeters in diameter.
Convert this length to inches. Solution: From our length conversion table, we know 1.5 cm
Round the result to 2 decimal that 2.54 cm = 1 in. This fact gives us two unit fractions:
places. 2.54 cm 1 in.
and . We use the unit fraction with cm in
1 in. 2.54 cm
the denominator so that these units divide out.
Unit fraction
2
12 cm 12 cm 1 in. ; Units to convert to 12 cm
12 cm = # 1 = # Copyright 2012 Pearson Education, Inc.
1 1 2.54 cm ; Original units
12 in.
Answer =
2.54
1. 0.59 in.
L 4.72 in. Divide.
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