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Math Help - Circle/triangle question

  1. #1
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    Circle/triangle question

    I was wondering if you guys could help me with this question. Ive been trying for hours, but Im breaking through.

    Find PT

    Note: Its a meant to be a circle
    PS is 25
    QR is the diameter of the circle
    Circle/triangle question-39362_426055749659_621434659_4603911_3609966_n-1-.jpg
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  2. #2
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    Quote Originally Posted by asaver View Post
    I was wondering if you guys could help me with this question. Ive been trying for hours, but Im breaking through.

    Find PT

    Note: Its a meant to be a circle
    PS is 25
    QR is the diameter of the circle
    Click image for larger version. 

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    If you draw a vertical line from P through the circle centre,
    mark where it touches the circle circumference, label it X.

    You can calculate the diameter as clearly the triangle QPR has 90 and 45 degree angles,

    so Sin45^o=\frac{R}{40}\ \Rightarrow\ Diameter=2R=80Sin45^o

    Next, triangle PXT is a right-angled triangle since PX is a diameter.
    You can calculate the angle XPS from

    Cos\theta=\frac{R}{25}\ \Rightarrow\ \theta=Cos^{-1}\left(\frac{R}{25}\right)

    The rest should be ok
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