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Gcse question help please

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    The question is that:

    Radius of sphere is 3cm
    radius of cone is 3cm

    TOTAL surface area of cone is equal to the surface area of the sphere workout the length of the slanted height.

    The book answer is 12, but i get 12 and 9

    my answer for 12 is (but this does not include the radius)

    pi*r*l=4*pi*r^2
    3*pi*l=36*pi
    l=12

    for 9 i use the total surface are of the cone meaning that i also incluse the circle at the bottom as it say total s.a.

    But when i use the total i get 9 when i use the curved suface i get 12 is this an error in the book or am i just missin something.

    Thanks.........
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    Did they say anywhere that it was an open cone? If it was a closed cone you would include the circle at the base

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Updated: February 29, 2012
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