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Math Help - Area of a triangle

  1. #1
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    Area of a triangle



    For question 4, given that the rectangle ABCD is folded along the diagonal BD, where AB = 4 and BC = 6, determine the area of BPD

    I struggled for half an hour figuring out why the poorly written solution is the solution, but for the life of me couldn't get the last step. Why is the area 1/2 BP x CD???
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  2. #2
    Senior Member MacstersUndead's Avatar
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    It took me a while to figure it out, but we know that

    BP = PD (deduced in the problem)
    AB = CD = 4
    because we were given a rectangle ABCD originally, and then we folded it.

    S = (1/2) BP * CD = (1/2) PD * AB = 26/3

    Now its easier to see PD is the base and AB is the height.

    EDIT: your h in the diagram would have to correspond to the base BD
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