Question 174070: 1)what is the exact value of cos 150
2)for a right tranigle ABC with A=40 degree, C=90 degree, b=15(not a degree). find a,c,B
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! 1)what is the exact value of cos 150
cos(150) = -cos(180-150) = -cos(3) = -sqrt(3)/2
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2)for a right tranigle ABC with A=40 degree, C=90 degree, b=15(not a degree). find a,c,B
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B = 90-40 = 50 degrees
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Now use the Law of Sines:
a/sin(A) = b/sin(B)
a = sin(40)[15/(sin(50))
a = 20.42
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c = sqrt(a^2+b^2)
c = sqrt(416.98 + 225) = 25.34
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Cheers,
Stan H.
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