mohon bantuannya nomot 1 bag d saja

Bab Trigonometri
Matematika SMA Kelas X

1d]
panjang sisi c
c = √(a² + b² - 2 x a x b x cos C)
c = √(4² + 6² - 2 x 4 x 6 x cos 120°)
c = √(16 + 36 - 2 x 24 x (-1/2))
c = √(52 + 24)
c = √76
c = 2√19 cm

a/sin A = c/sin C
4/sin A = (2√19)/sin 120°
sin A = 4 x 1/2 √3 : 2√19
sin A = 0,397
sudut A = 23,39°

sudut B = 180° - sudut A - sudut C
sudut B = 180° - 23,39° - 120°
sudut B = 36,61°