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2 5cm radius circles inscribed inside a 15cm circle

  1. Jan 21, 2009 #1


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    1. The problem statement, all variables and given/known data
    2 identical circles of radius 5cm touching each other externally and both are touching an arc length of a larger 15cm circle. Find the 1. perimeter and 2. area of the region between the 2 smaller circles and the arc length of the larger circle

    2. Relevant equations
    s=r times angle

    3. The attempt at a solution
  2. jcsd
  3. Jan 21, 2009 #2


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    Hi KKW! :smile:

    Hint: the line from the centre of the big circle to the two tangent points goes through the centres of the small circles. :wink:
  4. Jan 21, 2009 #3
    I really like this problem. I won't give away how I solved it but I'd be interested to know if others get the same answers.



    Note: The problem doesn't explicitly state if the two smaller circles lie inside or outside the larger circle. The values given above assume the former.
    Last edited: Jan 21, 2009
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