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Thread: Finding area and angles with sine ratio

  1. August 16th 2008, 06:10 AM #1
    BG5965
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    Finding area and angles with sine ratio

    The area of acute-angled isosceles triangle PQR is 8cm squared. PQ = QR = 6cm. Find angle PQR to 2 decimal places.

    I tried it and got 4/9, but its not right. Please help.
    Thankyou
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  2. August 16th 2008, 06:42 AM #2
    galactus
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    You just didn't finish.

    Area = \frac{1}{2}a^{2}sin{\theta}=8

    18sin{\theta}=8

    sin{\theta}=\frac{4}{9}

    {\theta}=sin^{-1}(\frac{4}{9})
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