Question

Find m∠A. A. 32 B. 26 C. 27 D. 30

Answer 1

Answer: B. 26

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Use law of cosines to find angle A

a^2 = b^2 + c^2 - 2*b*c*cos(A)

9^2 = 6^2 + 14^2 - 2*6*14*cos(A)

81 = 36 + 196 - 168*cos(A)

81 = 232 - 168*cos(A)

81 - 232  = -168*cos(A)

-151  = -168*cos(A)

-168*cos(A) = -151

cos(A) = (-151)/(-168)

cos(A) = 0.8988095

A = arccos(0.8988095)

A = 25.9979801

A = 26 degrees approximately