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Math Help - percentage change

  1. #1
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    Question percentage change

    How woulld yo answer this question and get all three marks?

    The width of a square is increased by 15%. Calculate the percentage change in the area of a square?

    thank you
    xx
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  2. #2
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    Quote Originally Posted by livyg123 View Post
    How woulld yo answer this question and get all three marks?

    The width of a square is increased by 15%. Calculate the percentage change in the area of a square?

    thank you
    xx

    Ok, you'd start off with a square, with four equal sides. Let's assign 100 to be the length of each of these sides. This means the area of the square is 100 * 100 = 10000.
    The width of the square is increased by 15%, (turning it into a rectangle), So now you have two sides of 100 and two of 115.
    110 * 115 = 11500 is the new area

    The change is 11500-10000 = 1500.
    As a percentage: 1500/10000 * 100 = 15%

    I think...
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