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Homework Help: Geometry Question. Confusing.

  1. Oct 26, 2005 #1
    A rectangle is split in half by a diagonal line creating two triangles
    The perimeter of a rectangle is 28 cm.
    The perimeter of each of the triangles is 24 cm.
    The diagonal of the reactangle is 2cm longer then the longer side of the rectangle.
    Find the length of the Diagonal.
    Ive tried trial and error of numbers, and i think i get it correct.
    Long sides of Rectangle= 8cm.
    Short Sides of rectangle= 4cm
    This gives a perimeter of 28.
    If the Long side of rectangle is 8. then the diagonal would be 10cm.
    it Follows the Pathagerom Thereom..
    but how would i go about solving this using three equations, with three unkown's..
  2. jcsd
  3. Oct 26, 2005 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    Short side = 4cm ? Are you sure ?

    You got the long side correctly.

    As for solving it : call the sides x and y and then translate each of the statements in the question into equations.
  4. Oct 26, 2005 #3
    Sorry I dont know how to do it. however I do know your answers don't work.
    perimeter of triangle = Diagonal+8+4=24
    Diagonal=12 (According to your solutions)
    a^2 + b^2=c^2
    8^2 + 4^2 must = 12^2 for your solutions to work

    64 + 16 does not = 144


    Do you have to use 3 equations and 3 unknowns?

    edit: Golkul just helped you alot more then I did
  5. Oct 26, 2005 #4
    Excuse, me the short Sides= 6cm and the Diagonal = 10... and the long side of rectangle=8

    Yes i have to make 3 equations with 3 unknowns

    and solve.
  6. Oct 26, 2005 #5
    so would this these to be correct so faR?

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