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Math Help - Solving angle in right triangle ABC

  1. #1
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    Solving angle in right triangle ABC

    I have a right triangle ABC. I know the measures of the opposite, hypoteneus, and adjacent sides.

    Using this picture:
    Image:Trigonometry triangle.svg - Wikipedia, the free encyclopedia

    I want to find angle A.

    I understand sin(A) = opposite / hypoteneus.

    How do I find what A is though?

    If I take arcsin(opposite/hypoteneus), it doesn't seem to give me the right answer (A).
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  2. #2
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    if you know the measure of two angles..you just do
    180-the two angles= you will find the third one
    the sum of angles in a triangle equals 180 and if it's right triangle
    it means the angle of adjacent and opposite are complementary which means
    angle adj.+angle op.=90
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  3. #3
    A riddle wrapped in an enigma
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    Quote Originally Posted by sstecken View Post
    I have a right triangle ABC. I know the measures of the opposite, hypoteneus, and adjacent sides.

    Using this picture:
    Image:Trigonometry triangle.svg - Wikipedia, the free encyclopedia

    I want to find angle A.

    I understand sin(A) = opposite / hypoteneus.

    How do I find what A is though?

    If I take arcsin(opposite/hypoteneus), it doesn't seem to give me the right answer (A).
    If you know the ratio of sin A (opposite/hypotenuse}, take the inverse sin of the ratio. On your calculator it should look like \sin^{-1}.

    For example, if \sin A = \frac{1}{2}, then \sin^{-1}=30
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