dalam segitiga ABC diketahui a=√5cm , b=3cm ,dan

a/sin A = b/sinB
√5/sin A = 3/sin 30°
√5/sin A = 3/(1/2)
√5 x 1/2 = 3 x sin A
√5/2 = 3 sin A
sin A = √5/2 x 1/3
sin A = √5/6 atau 1/6 √5

TRIGONOMETRI SMA X

Menurut aturan Sinus,
a/sin A = b/sin B

Maka,
√5/sin A = 3/sin 30°
√5/sin A = 3/ 1/2
1/2 √5 = 3 sin A
sin A = 1/2 √5 / 3
sin A = 1/6 √5