You can put this solution on YOUR website! in triangle ABC a=6 b=7 and c=8. what is the cos A in simplest fraction?
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Use Law of Cosines::
a^2 = b^2+c^2-2bc*cos(A)
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cos(A) = [b^2+c^2-a^2]/(2b*c)
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cos(A) = [49+64-36]/112 = 0.6875
A = cos^-1(0.6875) = 46.57 degrees
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Cheers,
Stan H.
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