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Summer Clouds moderators

31/10/2017 at 08:50
Answers
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A rectangle has a perimeter of 62 cm. If the length and width are each increased by 2 cm, by how many square centimeters does the area increase?




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    Phan Thanh Tinh Coordinator 01/11/2017 at 08:00

    Let a and b be the length and width of the rectangle in cm (a > b > 0), then 2a + 2b = 62

    The area of the new rectangle is :

    (a + 2)(b + 2) = ab + 2a + 2b + 4 = ab + 66

    So, the answer is 66 cm2

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  • ...
    tth 31/10/2017 at 10:09

    We have: The perimeter = 62 cm

    => \(\dfrac{1}{2}\) perimeter = 62 : 2 = 31 cm

    The area of the each increased is:

    2 . 2 = 4 cm

    So square centimeters does area increase is:

    4 . 31 = 124 cm2

    Ans: 124 cm2

    N/t: But I don't certain


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