Dalam segitiga ABC diketahui panjang sisi B = 6cm, besar sudut A = 30 derajat, mbesar sudut B = 30 derajat dab besar sudut C = 120 derajat. Maka panjang sisi ha

Aturan Sinus

AC = 6 cm
AB = x
BC = y

AC/SinB = BC/SinA
6/Sin30° = y/sin30°
6 = y
maka, BC = 6 cm

AC/SinB = AB/SinC
6/Sin30° = x/Sin120°
6/½ = x/½√3
6√3 = x
maka, AB = 6√3 cm

a / sin A = b / sin B
a = b / sin B × sin A
a = 6 cm / sin 30° × sin 30°
a = 6 cm / ½ × ½
a = 6 cm

c = b / sin B × sin C
c = 6 cm / sin 30° × sin C
c = 6 cm / sin 30° × sin 120°
c = 6 cm / ½ × ½√3
c = 10,392 cm