Question

MATH PROBLEM!! PLEASE HELP!! Explain your answer please

Answer 1

Answer:  angle B = 47 degrees

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Work Shown:

Use law of cosines to find angle B

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

9^2 = 6^2 + 12^2 - 2*6*12*cos(B)

81 = 36 + 144 - 144*cos(B)

81 = 180 - 144*cos(B)

81 - 180  = -144*cos(B)

-99  = -144*cos(B)

-144*cos(B) = -99

cos(B) = (-99)/(-144)

cos(B) = 0.6875

B = arccos(0.6875)

B = 46.5674634422102

B = 47 when rounding to the nearest whole number

Make sure your calculator is in degree mode.

arccos is the same as inverse cosine often labeled $\cos^{-1}$ on calculators.