diketahui segitiga lancip. panjang sisi AB =10 cm dan AC =12. jika nilai sin B = 4/5. tentukan nilai coc C

Bab Trigonometri
Matematika SMA Kelas XI

aturan cosinus
AC/sin B = AB/sin C
12 : (4/5) = 10 / sin c
sin C = 10 x (4/5) : 12
sin C = 40/60
sin C = 2/3 = y/r

x = √(r² - y²)
x = √(3² - 2²)
x = √(9 - 4)
x = √5

cos C = x/r
cos C = (√5) / 3
cos C = (1/3) √5