tolong kerjakan no 3

Mapel : Matematika
Kelas : X SMA
Bab : Trigonometri

Pembahasan :
Aturan Cosinus

Cos A = (b² + c² - a²)/2bc
Cos A = (7² + 8² - 6²)/2(7)(8)
Cos A = (49 + 64 - 36)/112
Cos A = 77/112
Cos A = 11/16
Cos A = 0,5
Cos A = Cos 60°
A = 60°

Cos B = (a² + c² - b²)/2ac
Cos B = (6² + 8² - 7²)/2(48)
Cos B = (36 + 64 - 49)/96
Cos B = 51/96
Cos B = 17/33
Cos B = 0,5
Cos B = Cos 60°
B = 60°

Sudut C = 180° - 2(60)°
Sudut C = 180° - 120°
Sudut C = 60°