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Math Help - find missing angle?

  1. #1
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    find missing angle?

    hi,
    i need to try and find the missing angle from this shape;
    find missing angle?-shapee.jpg

    would this be correct, sin?= 6xsin96/10= 0.6, inverse sin(0.6)= 36.87
    answer= 36.87????

    thanks
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  2. #2
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    e^(i*pi)'s Avatar
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    It's better to avoid using x to mean multiply. 6sin(96) is easy to understand. Let \theta be the angle you need to find

    \sin \theta = \dfrac{6\sin(96)}{10}

    Never round off halfway through a question, especially to one decimal place!

     \theta = \arcsin \left( \dfrac{6\sin(96)}{10}\right) = 36.6^{\circ} \text{  3sf }


    You've got the method, you just need to look at your rounding
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  3. #3
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    Your approach is certainly correct (law of sines). I get a very slightly different answer:

    \dfrac{\sin(?)}{6}=\dfrac{\sin(96^{\circ})}{10}

    \sin(?)=0.6\,\sin(96^{\circ})

    ?=\sin^{-1}(0.6\,\sin(96^{\circ}))\approx 36.63^{\circ}.
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  4. #4
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    Quote Originally Posted by andyboy179 View Post
    hi,
    i need to try and find the missing angle from this shape;
    Click image for larger version. 

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    would this be correct, sin?= 6xsin96/10= 0.6,

    (6sin96)/10=(6/10)sin96=0.6sin96

    inverse sin(0.6)= 36.87

    answer= 36.87????

    thanks
    You inadvertently dropped the sin96
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  5. #5
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    e^(i*pi)'s Avatar
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    I got the impression the answer was prematurely rounded to 0.6 since \sin(96) \approx 1
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