Please, soal nomor 11 tolong dijawab, beserta caranya yah Thanks!

Kelas 11 Matematika
Bab Trigonometri Lanjut
Kata Kunci : Aturan Sinus

∠A = ∠B

∠A + ∠B + ∠C = 180°
∠A + ∠A + 120° = 180°
2 . ∠A = 180° - 120°
∠A = 60°/2
∠A = 30°

BC/sin A = AB/sin C
30 cm/sin 30° = AB/sin 120°
AB = 30 . sin 120°/sin 30°
AB = 30 . 1/2 √3 / (1/2)
AB = 30√3 cm