Trapezoid

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vinay1983 Legendary Member
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Trapezoid

Post Sun Oct 06, 2013 8:38 am
Elapsed Time: 00:00
  • Lap #[LAPCOUNT] ([LAPTIME])
    If ABCD is a trapezoid, where AB is parallel to CD, what is the area of ABCD?

    (1) 2(AB) + CD = 12

    (2) The height of the trapezoid is 5 inches

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    Post Sun Oct 06, 2013 9:37 am
    vinay1983 wrote:

    If ABCD is a trapezoid, where AB is parallel to CD, what is the area of ABCD?

    (1) 2(AB) + CD = 12

    (2) The height of the trapezoid is 5 inches
    The area of the trapezoid is (average of the 2 "bases")(height)
    In other words, area = [(AB+CD)/2][height]

    Here are 2 trapezoids that satisfy the conditions in statements 1 and 2 combined.

    Trapezoid A

    Here, the area = 25

    Trapezoid B

    Here, the area = 22.5

    Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

    Answer = E

    Cheers,
    Brent

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    Post Tue Oct 08, 2013 8:48 am
    The formula for the area of a trapezoid is (1/2)*(base1 + base2)*height. In other words, it's the average of the two bases times the height. In this problem, it would be

    Area = (1/2)*(AB+CD)*height

    S1. Does not tell you anything about the height; insufficient
    S2. Does not tell you anything about the bases; insufficient

    Together, you know that 2AB+CD = 12 and the height is 5; however, you don't know the average of the two bases AB and CD.

    Answer: E

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