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PH Algebra II - Lesson 8.6, Try This "c"

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    PH Algebra II - Lesson 8.6, Try This "c"

    I think the book mixed up the formulas for the surface area of a sphere and for its volume. Try this "c" has: S=4π(r2), to be solved for r. This is the Surface formula. The solution in the back of the book makes no sense: r equals the square root of 3S over 4π. But things get more clear when one checks the Solution Key manual, which says r equals the third root of 3S over 4π, which would be the solution if the initial formula given had been the volume formula, V=4/3π(r3). So that's why I said there is confusion here with S and V.
    DS (15)
    DD (14)
    DS (7)

    Hi Mrs. Bee,

    I agree with your analysis.
    For the given problem, with the formula for surface area given and asked to solve for r, the correct answer should be:
    r = 1/2 [sqrt(S/pi)]
    Note: I would simplify by pulling out the 4 from under the sqrt sign to get 1/2 out front.

    Cindy Davis
    Science and Math teacher at Highlands Latin School - Indianapolis
    ds-26 college graduate: independent young adult
    ds-24 college graduate: 3rd year med school
    dd-22 college graduate: working as a registered nurse