Answer: angle X = 70.5 degrees
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Work Shown:
Law of Cosines
c^2 = a^2 + b^2 - 2ab*cos(C)
22^2 = 20^2 + 18^2 - 2*20*18*cos(X)
484 = 724 - 720*cos(X)
484 + 720*cos(X) = 724
720*cos(X) = 724 - 484
720*cos(X) = 240
cos(X) = 240/720
cos(X) = 1/3
X = arccos(1/3)
X = 70.528779
X = 70.5
Make sure your calculator is in degree mode.
