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Math Help - Once Again..Circles

  1. #1
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    Post Once Again..Circles

    If O is the center of the circle, BC = 10 and OC = 13, find OA. Please explain! Thank you so much for any help!
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by IHATECHONGAS View Post
    If O is the center of the circle, BC = 10 and OC = 13, find OA. Please explain! Thank you so much for any help!
    The line OA intersects the chord BC at a right angle. Thus A is the midpoint of BC. Can you take it from here?

    -Dan
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  3. #3
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    So OA = 5?...I think lol
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by IHATECHONGAS View Post
    So OA = 5?...I think lol
    No, AC = 5, since A is the midpoint of BC which is 10 units long. We need to use Pythagoras' Theorem to find OA.

    By Pythagoras' Theorem:

    OA^2 = 13^2 - 5^2 = 169 - 25 = 144
    => OA = sqrt(144) = 12
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  5. #5
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    Smile

    Thank you very much for the explaination! I was so confused! lol Thanx a mil!
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