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Math Help - Circle Geometry

  1. #1
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    Circle Geometry



    Find the diameter of the crcle that passes through A, B and C.

    Could someone please explain to me how to do this? Any hints?
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by xwrathbringerx View Post


    Find the diameter of the crcle that passes through A, B and C.

    Could someone please explain to me how to do this? Any hints?
    First draw a proper diagram showing the circle, the centre and a few other auxillary lines. Then fill in what you know on the diagram.

    See the attachment (P is the foot of the perpendicular from O onto AC). Can you explain all the values in this diagram?

    You should be able to find the diameter of the circle easily once you use the sine rule to find the length of AC.

    RonL
    Attached Thumbnails Attached Thumbnails Circle Geometry-gash.jpg  
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  3. #3
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    errr sori but i dont seem to get you...i know how you got those values but i dont understand how they get me closer to finding the diameter
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  4. #4
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    Quote Originally Posted by xwrathbringerx View Post
    errr sori but i dont seem to get you...i know how you got those values but i dont understand how they get me closer to finding the diameter
    Because OAP is a 30,60,90 degree triangle so the relationship between the sides is known.

    You know the length of AC by the sine rule, so you can find the length of OA, the radius, and twice that is the diameter which is what you need to find.

    RonL
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  5. #5
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    oh rite thanx
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