• Choice D

    The trapezoid has a top side of 3232 and two equal legs of 1010. The bottom base is shorter. Drop perpendiculars from the ends of the shorter base to form right triangles.

    The difference in the bases is 3212=2032 - 12 = 20, so each right triangle has a horizontal leg of:

    32122=202=10\frac{32 - 12}{2} = \frac{20}{2} = 10

    Wait — let me reconsider. The base is 3232 and each leg is 1010. Drop altitudes from the top vertices to the base. Each horizontal segment is:

    32122=10\frac{32 - 12}{2} = 10

    But that would make the horizontal leg equal to the hypotenuse, which is impossible. Let me re-read: the top is 3232 and the bottom is shorter. Actually, the base (bottom) of the trapezoid can be found:

    Half the difference=32bottom2\text{Half the difference} = \frac{32 - \text{bottom}}{2}

    Using the Pythagorean theorem with leg =10= 10 and the altitude hh:

    h2+62=102h^2 + 6^2 = 10^2

    h2=10036=64h^2 = 100 - 36 = 64

    h=8h = 8

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