*n.***1. ** The act of measuring or the process of being measured.
**2. ** A system of measuring: *measurement in miles.*
**3. ** The dimension, quantity, or capacity determined by measuring: *the measurements of a room.*
## CONVERSION BETWEEN METRIC AND U.S. CUSTOMARY UNITS### FROM U.S. CUSTOMARY TO METRICWhen You Know | Multiply By | To Find |
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inches | 25.4 | millimeters | | 2.54 | centimeters | feet | 30.48 | centimeters | yards | 0.91 | meters | miles | 1.61 | kilometers | teaspoons | 4.93 | milliliters | tablespoons | 14.79 | milliliters | fluid ounces | 29.57 | milliliters | cups | 0.24 | liters | pints (liquid) | 0.47 | liters (liquid) | quarts (liquid) | 0.95 | liters (liquid) | gallons | 3.79 | liters | cubic feet | 0.028 | cubic meters | cubic yards | 0.76 | cubic meters | ounces | 28.35 | grams | pounds | 0.45 | kilograms | short tons (2,000 lbs) | 0.91 | metric tons | square inches | 6.45 | square centimeters | square feet | 0.09 | square meters | square yards | 0.84 | square meters | square miles | 2.59 | square kilometers | acres | 0.40 | hectares |
### FROM METRIC TO U.S. CUSTOMARYWhen You Know | Multiply By | To Find |
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millimeters | 0.04 | inches | centimeters | 0.39 | inches | meters | 3.28 | feet | | 1.09 | yards | kilometers | 0.62 | miles | milliliters | 0.20 | teaspoons | | 0.07 | tablespoons | | 0.03 | fluid ounces | liters (liquid) | 1.06 | quarts (liquid) | | 0.26 | gallons | | 4.23 | cups | | 2.12 | pints (liquid) | cubic meters | 35.31 | cubic feet | | 1.35 | cubic yards | grams | 0.035 | ounces | kilograms | 2.20 | pounds | metric tons (1,000 kg) | 1.10 | short tons | square centimeters | 0.155 | square inches | square meters | 1.20 | square yards | square kilometers | 0.39 | square miles | hectares | 2.47 | acres |
### TEMPERATURE CONVERSION BETWEEN CELSIUS AND FAHRENHEIT°C = (°F - 32) ÷ 1.8 | °F = (°C × 1.8) + 32 |
## UNITS OF THE INTERNATIONAL SYSTEMThe International System (abbreviated SI, for Système International, the French name for the system) was adopted in 1960 by the 11th General Conference on Weights and Measures. An expanded and modified version of the metric system, the International System addresses the needs of modern science for additional and more accurate units of measurement. The key features of the International System are decimalization, a system of prefixes, and a standard defined in terms of an invariable physical measure. ### BASE UNITSThe International System has base units from which all others in the system are derived. The standards for the base units, except for the kilogram, are defined by unchanging and reproducible physical occurences. For example, the meter is defined as the distance traveled by light in a vacuum in 1/299,792,458 of a second. The standard for the kilogram is a platinum-iridium cylinder kept at the International Bureau of Weights and Standards in Sèvres, France. Unit | Quantity | Symbol |
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meter | length | m | kilogram | mass | kg | second | time | s | ampere | electric current | A | kelvin | temperature | K | mole | amount of matter | mol | candela | luminous intensity | cd |
### PREFIXESA multiple of a unit in the International System is formed by adding a prefix to the name of that unit. The prefixes change the magnitude of the unit by orders of ten from 1024 to 10-24. Prefix | Symbol | Multiplying Factor |
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yotta- | Y | 1024 = 1,000,000,000,000,000,000,000,000 | zetta- | Z | 1021 = 1,000,000,000,000,000,000,000 | exa- | E | 1018 = 1,000,000,000,000,000,000 | peta- | P | 1015 = 1,000,000,000,000,000 | tera- | T | 1012 = 1,000,000,000,000 | giga- | G | 109 = 1,000,000,000 | mega- | M | 106 = 1,000,000 | kilo- | k | 103 = 1,000 | hecto- | h | 102 = 100 | deca- | da | 10 = 10 | deci- | d | 10-1 = 0.1 | centi- | c | 10-2 = 0.01 | milli- | m | 10-3 = 0.001 | micro- | μ | 10-6 = 0.000,001 | nano- | n | 10-9 = 0.000,000,001 | pico- | p | 10-12 = 0.000,000,000,001 | femto- | f | 10-15 = 0.000,000,000,000,001 | atto- | a | 10-18 = 0.000,000,000,000,000,001 | zepto- | z | 10-21 = 0.000,000,000,000,000,000,001 | yocto- | y | 10-24 = 0.000,000,000,000,000,000,000,001 |
### DERIVED UNITSMost of the units in the International System are derived units, that is units defined in terms of base units and supplementary units. Derived units can be divided into two groups—those that have a special name and symbol, and those that do not. WITHOUT NAMES AND SYMBOLS |
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Measure of | Derivation |
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acceleration | m/s2 | angular acceleration | rad/s2 | angular velocity | rad/s | density | kg/m3 | electric field strength | V/m | luminance | cd/m2 | magnetic field strength | A/m | velocity | m/s |
WITH NAMES AND SYMBOLS |
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Unit | Measure of | Symbol | Derivation |
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coulomb | electric charge | C | A·s | farad | electric capacitance | F | A·s/V | henry | inductance | H | V·s/A | hertz | frequency | Hz | cycles/s | joule | quantity of energy | J | N·m | lumen | flux of light | lm | cd·sr | lux | illumination | lx | lm/m2 | newton | force | N | kg·m/s2 | ohm | electric resistance | Ω | V/A | pascal | pressure | Pa | N/m2 | tesla | magnetic flux density | T | Wb/m2 | volt | voltage | V | W/A | watt | power | W | J/s | weber | magnetic flux | Wb | V·s |
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