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Homework Help: Area of a Parallelogram from 3D points

  1. Apr 27, 2010 #1
    1. The problem statement, all variables and given/known data

    Find the area of the parallelogram with vertices:

    P(0,0,0), Q(-3,0,-1), R(-3,1,0), S(-6,1,-1)

    2. Relevant equations
    A=BH


    3. The attempt at a solution

    I think I know why this is incorrect, but i dont know what else to try.

    I found vector PQ and called it a, vector PR called it b, vector PS called it c.
    Then did a dot (b cross c)=3 but thats incorrect.

    I basically found the volume, but idk how to find the area.
    Any suggestions I should try?
     
  2. jcsd
  3. Apr 27, 2010 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi somebodyelse5! :wink:

    The area of a parallelogram is (±) one side "cross" the next side. :smile:
     
  4. Apr 27, 2010 #3
    Thanks! wow that was a pretty stupid question on my part, I should have known how to do that, especially since thats the first step in finding the volume of a parallepiped (sp?)

    Thanks, got it figured out!
     
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