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Homework Help: Radius of a circle

  1. Dec 15, 2008 #1
    1. The problem statement, all variables and given/known data


    2. Relevant equations

    Why is there negative on h-2k+2?and a denominator of negative square root of 5?
    also in 2h-k-17, it has a negative sign but the denominator is not negative square root of 5? I really don't understand this part... please explain :frown:

    3. The attempt at a solution
  2. jcsd
  3. Dec 15, 2008 #2


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    Homework Helper

    In this problem center of the circle lies between the two tangents. In such cases, to find the perpendicular distances, you have to make the constant C in the tangent positive.
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