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Chapter 8—Measurements

8-3 Converting Between the U.S. Standard and Metric Systems

The official system of measurement for most of the world today is the metric system. The United States and a couple smaller countries do not. Actually, the U.S. uses both the U.S. Customary system and the metric system. This is why it is important for people in the USA, and others who visit or do business with the United States, master the simple processes for converting between U.S. Customary and metric systems of measurement.

Converting Lengths

The most common length conversions are between:

  • Inches (US) and centimeters (metric)
  • Feet (US) and meters (metric)
  • Miles (US) and kilometers (metric)

Facts

Procedures

Inches and Centimeters

1 in = 2.54 cm

Inches and Centimeters
  • To convert inches to centimeters: Multiply the number of inches by 2.54.
  • To convert centimeters to inches: Divide the number of centimeters by 2.54.
Feet and Meters

1 m = 3.28 ft

Feet and Meters
  • To convert feet to meters: Divide the number of feet by 3.28.
  • To convert meters to feet: Multiply the number of meters by 3.28.
Miles and Kilometers

1 mi = 1.61 km

Miles and Kilometers
  • To convert miles to kilometers: Multiply the number of miles by 1.61.
  • To convert kilometers to miles: Divide the number of kilometers by 1.61.

Examples of Common Length Conversions

Examples & Exercses

Converting Lengths

Use these interactive examples and exercises to strengthen your understanding and build your skills:

Express units of inches, feet, and miles as decimal values.

Conversions are not always as tidy as those in the previous examples and exercises. For example, US Customary units of length are not always expressed in decimal forms you are more likely to see 41/2 inches than 4.5 inches, and more likely to see 4' 3" than 4.25 ft. There is a trend toward using decimal values for US Customary units, but we have to know how to deal with both forms.  The following examples deal with the less-tidy forms.

Examples of More Complicated Length Conversions

So that's how you convert inches and feet to centimeters and meters. But what if you need to convert millimeters to inches or miles to kilometers? Naturally there are conversion factors for such conversions for all possible combinations of conversions, in fact. People, however, don't like having to memorize so many different conversion factors. So we memorize a few of the most important conversion factors, then work out the other conversions whenever we need them.

Suppose, for instance, you need to convert some number of millimeters to inches. You probably don't know the conversion factor for millimeters to inches, but you do know the conversion factor for centimeters to inches. It is listed just above this place on your screen. All you need to do is (1) convert the millimeters to centimeters (you know that conversion factor), and (2) use your cm-to-inches conversion.

Suppose you need to convert yards to meters, but you don't happen to know the conversion factors for yards and meters. However, you should know the conversion factors for feet and yards ( 3 ft/yd) and you should likewise know the conversion factor for feet and meters ( 3.28 ft/m). So you can convert yards to feet and then feet to meters.

Examples:

Problem 1: Convert 10 yards to meters
(Assume you do not know the conversion factor for yards and meters)

  1. Convert 10 yd to ft.

10 yd x 3 ft/yd = 30 ft

  1. Convert 30 ft to m

30 ft 3.28 ft/m = 9.15 m

Ans. 10 yd = 9.15 m

Problem 2: convert 32 cm to feet and inches
(Assume you do not know the conversion factor for centimeters and feet)

  1. Convert 34 cm to in.

34 cm 2.54 cm/in = 13.39 in

  1. Convert 13.39 in to ft.

13.39 in 12 in/ft = 1.12 ft

 

Examples & Exercses

Converting Lengths

Use these interactive examples and exercises to strengthen your understanding and build your skills:

 

Converting Capacities

The most common capacity conversions are between:

  • Fluid ounces (US) and milliliters (metric)
  • Gallons (US) and liters (metric)

Facts

Procedures

Fluid Ounces and Milliliters

1 fl. oz = 29.57 mL

Fluid Ounces and Milliliters
  • To convert fluid ounces to milliliters: Multiply the number of fluid ounces by 29.57.
  • To convert milliliters to fluid ounces: Divide the number of milliliters by 29.57.
Gallons and Liters

1 gal =  3.79 L

Gallons and Liters
  • To convert gallons to liters: Multiply the number of gallons by 3.79.
  • To convert liters to gallons: Divide the number of liters by 3.79.

Examples

 

Examples

 

But what about converting between units such as quarts and liters? Convert quarts to gallons, first. Then use the gallons-to-liters conversion to get your answer.

 

Examples

 

Examples & Exercises

Converting Capacities

Use these interactive examples and exercises to strengthen your understanding and build your skills:

Converting Weights

  • 1 kg = 2.2 lb

Procedure

  • To convert pounds to kilograms: Multiply the number of pounds by 0.4536.
  • To convert kilograms to pounds: Multiply the number of kilograms 2.2.

 

Examples

 

 

  • 1 oz = 28.35 gm
  • 1 gm = 0.035 oz

Procedure

  • To convert ounces to grams: Multiply the number of ounces by 28.35.
  • To convert grams to ounces: Multiply the number of grams by 0.035.

Examples

 

Examples & Exercises

 

 

David L. Heiserman, Editor

Copyright   SweetHaven Publishing Services
All Rights Reserved

Revised: June 06, 2015