In δdef, de = 11, ef = 9, and angle e = 140°. which equation correctly uses the law of cosines to solve for the third side? e2 = 112 92 − 2(11)(9)cos(140°) 112 = e2 92 − 2e(9)cos(140°) 92 = e2 112 − 2e(11)cos(140°) e = 11 9 − 2(11)(9)cos(140°)
I believe the correct answer from the choices listed above is the first option. The equation that correctly ses the law of cosines to solve for the third side would be e2 = 11^2 + 9^2 − 2(11)(9)cos(140°). Hope this answers the question. Have a nice day.
