The Main Idea

Units of Length

Length is the distance from one end of an object to the other end, or from one object to another. The system for measuring length in the United States is based on the four customary units of length: inch, foot, yard, and mile.

Unit Equivalents	Conversion Factors (longer to shorter units of measurement)	Conversion Factors(shorter to longer units of measurement)
[latex]1[/latex] foot [latex]= 12[/latex] inches	[latex]\displaystyle \frac{12\ \text{inches}}{1\ \text{foot}}[/latex]	[latex]\displaystyle \frac{1\text{ foot}}{12\text{ inches}}[/latex]
[latex]1[/latex] yard [latex]= 3[/latex] feet	[latex]\displaystyle \frac{3\ \text{feet}}{1\ \text{yard}}[/latex]	[latex]\displaystyle \frac{1\text{ yard}}{3\text{ feet}}[/latex]
[latex]1[/latex] mile [latex]= 5,280[/latex] feet	[latex]\displaystyle \frac{5,280\text{ feet}}{1\text{ mile}}[/latex]	[latex]\displaystyle \frac{\text{1 mile}}{\text{5,280 feet}}[/latex]

Units of Weight

When you mention how heavy or light an object is, you are referring to its weight. Weight is measured in the U.S. customary system using three units: ounces, pounds, and tons.

Unit Equivalents	Conversion Factors (heavier to lighter units of measurement)	Conversion Factors(lighter to heavier units of measurement)
[latex]1[/latex] pound = [latex]16[/latex] ounces	[latex]\frac{16\text{ ounces}}{1\text{ pound}}[/latex]	[latex]\displaystyle \frac{\text{1 pound}}{\text{16 ounces}}[/latex]
[latex]1[/latex] ton = [latex]2000[/latex] pounds	[latex]\frac{2000\text{ pounds}}{1\text{ ton}}[/latex]	[latex]\displaystyle \frac{\text{1 ton}}{\text{2000 pounds}}[/latex]

Units of Capacity

Capacity is the amount of liquid (or other pourable substance) that an object can hold when it’s full. There are five main units for measuring capacity in the U.S. customary measurement system – fluid ounce, cup, pint, quart, and gallon.

Unit Equivalents	Conversion Factors (heavier to lighter units of measurement)	Conversion Factors (lighter to heavier units of measurement)
[latex]1[/latex] cup = [latex]8[/latex] fluid ounces	[latex]\displaystyle \frac{\text{1 cup}}{\text{8 fluid ounces}}[/latex]	[latex]\displaystyle \frac{\text{8 fluid ounces}}{\text{1 cup}}[/latex]
[latex]1[/latex] pint = [latex]2[/latex] cups	[latex]\displaystyle \frac{\text{1 pint}}{2\text{ cups}}[/latex]	[latex]\displaystyle \frac{2\text{ cups}}{1\text{ pint}}[/latex]
[latex]1[/latex] quart = [latex]2[/latex] pints	[latex]\displaystyle \frac{\text{1 quart}}{2\text{ pints}}[/latex]	[latex]\displaystyle \frac{2\text{ pints}}{\text{1 quart}}[/latex]
[latex]1[/latex] quart = [latex]4[/latex] cups	[latex]\displaystyle \frac{\text{1 quart}}{4\text{ cups}}[/latex]	[latex]\displaystyle \frac{4\text{ cups}}{\text{1 quart}}[/latex]
[latex]1[/latex] gallon = [latex]4[/latex] quarts	[latex]\displaystyle \frac{\text{1 gallon}}{4\text{ quarts}}[/latex]	[latex]\displaystyle \frac{4\text{ quarts}}{\text{1 gallon}}[/latex]
[latex]1[/latex] gallon = [latex]16[/latex] cups	[latex]\displaystyle \frac{1\text{ gallon}}{\text{16 cups}}[/latex]	[latex]\displaystyle \frac{\text{16 cups}}{1\text{ gallon}}[/latex]