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Math Help - Can someone please check my work in calculating this area?

  1. #1
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    Can someone please check my work in calculating this area?

    Okay, I needed to find the area of this figure: http://i25.tinypic.com/symtyt.jpg

    So I figured out that each side had a total area of 224 (8*28), so the two combined would be 448, if they were separate. Since they overlap, I needed to subtract the area of the triangle from this. Using heron's formula, I plugged in the numbers: 1/2(14+14+8) --> square root of 18(18-14)(18-14)(18-8) --> square root of 18*4*4*10 --> square root of 2880. The square root of 2880 is 53.665.

    So, I did 448-53.665=394. Is this correct?
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  2. #2
    Member eXist's Avatar
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    I disagree. The 2 parallelograms should have an area of 431.2 (7.7 * 28 * 2).

    But you are right about subtracting the triangle. There is an easier way then using hero's formula.

    Drop a height on the triangle and you have this:


    Now use the Pythagorean theorem to calculate the height. Just easier in my opinion.
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  3. #3
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    Thank you so much!!
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