The Metric System of Measurement

The Metric system of measurement is an internationally agreed decimal system created in 1799 by a group of French scientists to simplify measurement. The international System of Units (SI), the official system of measurement in almost every country in the world, is based upon the metric system.

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While the metric system was lawfully accepted for use in the United States in 1866, the US has not adopted the metric system as its "official" system of measurement.

In the metric system, each basic type of measurement (length, weight, capacity) has one basic unit of measure (meter, gram, liter). Conversions are quickly made by multiplying or dividing by factors of 10. It is a simple as moving the decimal point to the right (for smaller prefixes) or to the left (for larger prefixes).

To remember the proper movement, arrange the prefixes from largest to smallest.

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Kilo  means thousand (1000)
Hecto means hundred (100)
Deca means ten (10)
Deci means one-tenth (1/10)
Centi means one-hundredth (1/100)
Milli means one-thousandth (1/1000)

Length:
1 kilometer (km) = 1000 meters
1 centimeter (cm) = .01 meter
1 millimeter = .001 meter (m)
Weight:
1 kilogram (kg) = 1000 grams (g)
1 milligram (mg) = .001 gram
Capacity:
1 milliliter (ml)= .001 liter (l)

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Conversion Ratio (or Unit Factor): A conversion ratio (or unit factor) is a ratio equal to one. This ratio carries the names of the units to be used in the conversion. It can be used for conversions within the English and Metric Systems, as well as for conversions between systems. The conversion ratio is based upon the concept of equivalent values. In the example below, 1000 meters is substituted for its equivalent measure of 1 kilometer.
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Proportions will help you make conversions
when working with measurements.

Create a unit conversion ratio, which is always equal to 1:  mm1 

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ex1 Convert 1.254 kilometers to meters.
Solution using Unit Conversion:
There are 3 feet in one yard, so the conversion ratio is 1 yard / 3 feet.
mm3
ANSWER: 1254.0 meters
mm4
Solution using listing of prefixes: Notice from the prefix chart that meter is three places to the right of the prefix kilo. This tells us to move the decimal point three places to the right. The answer is 1254.0 meters.

 

ex2 Convert 650 mL to daL. (mL is milliliters and daL is decaliters).
Solution using listing of prefixes: Notice in the listing above that the prefix deca is four places to the left of the prefix milli. This tells us to move the decimal point four places to the left. The answer is 0.0650 daL. (Note: dL is deciliters, daL is decaliters.)

 

ex3 Convert 750 grams to milligrams.
Solution using listing of prefixes:
Notice in the listing above that the prefix
milli is three places to the right of gram. This tells us to move the decimal point three places to the right. The answer is 750,000 milligrams.

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