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16 votes
16 votes
THIS IS DUE SOON! PLEASE SOMEONE HELP!!! IM SO CONFUSED!!! SHOW ME STEP BY STEP PLEASE! QUESTION IS IN PICTURE BELOW!

THIS IS DUE SOON! PLEASE SOMEONE HELP!!! IM SO CONFUSED!!! SHOW ME STEP BY STEP PLEASE-example-1
User Ashutosh Patole
by
3.0k points

1 Answer

20 votes
20 votes

Answer: 62.2 degrees

=========================================================

Step-by-step explanation:

The given side lengths are

  • a = 9
  • b = 5
  • c = 8

Use the law of cosines to determine angle C.


c^2 = a^2 + b^2 - 2*a*b*\cos(C)\\\\8^2 = 9^2 + 5^2 - 2*9*5*\cos(C)\\\\64 = 106 - 90*\cos(C)\\\\64-106 = -90\cos(C)\\\\-42 = -90\cos(C)\\\\-90\cos(C) = -42\\\\\cos(C) = -42/(-90)\\\\\cos(C) \approx 0.4666667\\\\C \approx \cos^(-1)(0.4666667)\\\\C \approx 62.1818586^(\circ)\\\\C \approx 62.2^(\circ)

Make sure your calculator is in degree mode.

User Talonmies
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3.3k points