Answer:
41.4
Step-by-step explanation: Since this isn't a right triangle and you're given side side side (SSS), you need the Law of Cosines.
cos(c) = (a^2 + b^2 - c^2)/2ab
(100+144-64)/2*12*10
cos(c) = 180/240
multiply both sides of the equation by cos^-1 to get ride of cos:
cos^-1(cos(c)) = cos^-1(180/240)
c = 41.4
