Question

Select the angle that correctly completes the law of cosines for this triangle. 72 + 252 – 2(7)(25)cos ___ = 242 A. 180° B. 90° C. 16° D. 74°

Answer 1

x =76.45 degrees

Explanation:

72 + 252 – 2(7)(25)cos _x__=242

combine like terms

324-350cosx = 242

subtract 324 from each side

-350x = -82

divide by -350

cos x = -82/-350

cos x = 82/350

take the arccos of each side

arccos (cos x) = arccos (82/350)

x =76.45 degrees