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Homework Help: Converting Measurements

  1. Sep 1, 2010 #1
    I'm not understanding the steps when trying to convert.

    The question is...
    convert 43 cm to kilometers.

    centi-10^-2
    kilo--10^3

    Now, i'm not sure as to what steps I use in order to get the correct answer.
    If someone could explain to me how i'd really appreciate it.
    (: thanks.
     
  2. jcsd
  3. Sep 1, 2010 #2

    berkeman

    User Avatar

    Staff: Mentor

    The real trick to units conversions it to always multiply by 1. That's pretty much it.

    So to convert from x inches to yards, multiply x [inches] by this "1" [tex]1 = \frac{1 yd}{36 inches}[/tex]

    As long as you multiply something by 1, it doesn't change its value, right? You just need to set up the "1" fraction, with the units you want to cancel on the bottom, and the units you want in the end on the top. After you multiply though in my example, you end up with the units "inches" on both the top and bottom of the fraction, so they cancel out, and you are left with units of "yards" on top, which is what you want your answer in.

    In general, carry units along with all quantities, and cancel them out when they appear on both the top and bottom of a fraction.

    Now, can you show us how to do the conversion in your problem?


    EDIT -- Welcome to the PF, BTW.
     
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