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Math Help - problem in solid geometry

  1. #1
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    problem in solid geometry

    if ABC is a triangle where AB = 5cm , AC = 3cm , D is the midpoint of BC and draw AH = (6 *root 2)cm perpendicular to both AC and AB . find the length of DH

    problem in solid geometry-8-31-2012-10-48-29-pm.png
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  2. #2
    Senior Member MaxJasper's Avatar
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    Re: problem in solid geometry

    Image is wrong if AH=6*squrt(2)=8.485 cm. Is AH perpendicular to BC? You say it is prep to both AC & AB!!!!!!?!??!
    Last edited by MaxJasper; August 31st 2012 at 02:20 PM.
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  3. #3
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    Re: problem in solid geometry

    Hello, mido22!

    ABC is a triangle where AB = 5cm, AC = 3cm, D is the midpoint of BC.
    Draw AH = 6√2 cm, perpendicular to both AC and AB.
    Find the length of DH.

    The diagram looks like this.
    Code:
                H
                o
                | *
               *|  _*
                |6√2 *
              * |       *
                |         *
             *  o - - - - - o B
               *A    5   *
            * *       *
             *3    o
           **   *   D
           * *
          o
          C
    I don't see a unique length for D\!H.

    It depends on \theta = \angle B\!AC.

    If \theta = 0^o,\:D\!H = 7\sqrt{2}

    If \theta = 180^o,\:D\!H = 6\sqrt{2}
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  4. #4
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    Re: problem in solid geometry

    sorry i forgot to write that BC = 7 cm

    <BAC not zero and not 180

    i have a final answer that HD = 2.5 but i can't find a proof
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  5. #5
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    Re: problem in solid geometry

    i can prove that AH is perpendicular to BC since it is perpendicular to both AB , AC but then i don't know >>
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