TOLONG BANTU YAK KELAS 10 MAT NIH

Mapel : Matematika
Kelas : X SMA
Bab : Trigonometri

Pembahasan :
Aturan Sinus

a/Sin A = b/Sin B
8/Sin A = 12/Sin 30
8/Sin A = 12/(1/2)
4 = 12Sin A
Sin A = 1/3

Cos A = √[1 - (1/3)²]
Cos A = √[1 - (1/9)]
Cos A = √[8/9]
Cos A = 2/3 √2