Arithmetic Grade Four

Lesson One hundred and forty-six: METRIC LENGTH

Inches, feet, yards, and miles are all examples of English units for measuring length. Another system exists for measuring length. It is known as the metric system. Metric units for measuring length include the millimeter, centimeter, meter, and kilometer (as well as others). Here are how the metric units scale compared to each other. 


         10 millimeters = 1 centimeter
         100 centimeters = 1 meter
         1000 meters = 1 kilometer

WHICH MEANS THAT:

        100,000 centimeters = 1 kilometer
       1,000,000 millimeters = 1 kilometer
        1000 millimeters = 1 meter
You can probably tell that millimeters are used to measure really small things and that centimeters are used to measure somewhat less small things. A meter is slightly longer than a yard. A kilometer is about two-thirds of a mile. In fact, if you are at all familiar with the sport of track and field you may have heard of the following running races: 
 
            OLD RACE   |    NEW RACE
          -------------|----------------
        100 yard dash  |  100 meter sprint
        440 yard run   |  400 meter run
        880 yard run   |  800 meter run
        mile run       |  1500 meter run
                       |
In the United States we still use English units more often than we use metric units. For instance, highway signs display distances in miles and speed limits in miles per hour. A football field is 100 yards long. You can go to a sandwich shop and get a six inch submarine sandwich or a foot long hot dog.

However, it is still a good idea to at least understand how the metric system works and what some of the common metric units are. If you go to Canada, road signs display distances in kilometers and speed limits in kilometers per hour. Many wrench sets use metric units for socket size. Also guitar string thickness is often represented in metric units.

Also if you are into track and field you may have heard of the following races: 


      Running Race Distance    |   Translation into English units
    ---------------------------|----------------------------------
        5000 meter or 5km      |      3.1 miles
       10000 meter or 10km     |      6.2 miles
       25000 meter or 25km     |     15.5 miles
                               |

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