Page 415 - Basic College Mathematics with Early Integers

392 C HAPTE R 5 I RATIO, PROPORTION, AND MEASUREMENT

PRACTICE 9 Example 9 Convert 2.3 m to centimeters.
Convert 2.5 m to millimeters.
Solution: First we will convert by using a unit fraction.
Unit fraction
2
2.3 m 100 cm
2.3 m = # = 230 cm
1 1 m
Now we will convert by listing the units of length in order from left to right and
moving from meters to centimeters.

km hm dam m dm cm mm
2 units to the right
2.30 m=230. cm
2 places to the right
With either method, we get 230 cm.

Work Practice 9

PRACTICE 10 Example 10 Convert 450,000 mm to meters.
Convert 3500 m to kilometers.
Solution: We list the units of length in order from left to right and move from
millimeters to meters.

km hm dam m dm cm mm
3 units to the left
450,000 mm=450.000 m or 450 m

Work Practice 10

Concept Check What is wrong with the following conversion of 150 cm to
meters?

150.00 cm = 15,000 m
Î

Objective Performing Operations on Metric System
Units of Length

To add, subtract, multiply, or divide with metric measurements of length, we write
all numbers using the same unit of length and then add, subtract, multiply, or divide
as with decimals.

PRACTICE 11 Example 11 Subtract 430 m from 1.3 km.
Subtract 640 m from 2.1 km.
Solution: First we convert both measurements to kilometers or both to meters.
430 m=0.43 km or 1.3 km =1300 m

Answers 1.30 km 1300 m
9. 2500 mm 10. 3.5 km – 0.43 km – 430 m Copyright 2012 Pearson Education, Inc.
11. 1.46 km or 1460 m 0.87 km 870 m
The difference is 0.87 km or 870 m.
Concept Check Answer
decimal point should be moved two Work Practice 11
places to the left: 1.5 m