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Homework Help: A man standing x ft. from a light pole, length of man's shadow?

  1. Jul 8, 2012 #1
    1. The problem statement, all variables and given/known data
    A man 6ft. tall is standing x ft. from a light pole 15 ft. high. Express the length of the man's shadow L as a function of x.

    2. Relevant equations

    3. The attempt at a solution
    I assumed that the man's shadow creates another like triangle within in the larger one. The base of the large triangle is L + x and the height is 15 ft.
    The base of the small triangle is L and the height 6 ft.

    I set 15/(L+x) = (6/L) and solved for L. My solution was L(x)=(2/3)x, however, the book says it's L(x)=(3/2)x. Is it a typo or am I doing something wrong?
  2. jcsd
  3. Jul 8, 2012 #2


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    Gold Member

    Your process is correct and your answer is correct
  4. Jul 8, 2012 #3


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    Homework Helper

    Looks fine to me. The book's solution is a typo.

    EDIT: Oops, beaten to it by phinds. :wink:
  5. Jul 8, 2012 #4
    Thanks guys.
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