Verified answer

180 -75 + 45 = 60°

lei dos senos

x / seno60 = 7,1/ seno45

x / 0,87 = 7,1/0,71

x.0,71 = 7,1.0,87

x.0,71 = 6,177

x = 6,177 / 0,71

x = 8,7