jawab dikumpulkan sekarang ?

gunakan aturan sinus
AB / sin(C) = BC / sin(A)
12 / sin(30) = BC / sin(60)
BC = sin(60) × 12 / sin(30)
BC = 1/2√3 × 12 / 1/2
BC = 12 √3 cm
atau = 20,78 cm