Jawaban:
cos A = 4/5 = sa/mi
de = akar (5² – 4²)
de = akar (25-16)
de= √9 = 3
sin A = de/mi = 3/5
sin B = 12/13 = de/mi
sa = akar (13²- 12²)
sa = akar (169-144)
sa =√25 = 5
cos B = sa/mi = 5/13
A + B + C = 180
C = 180 – (A + B)
sin C = sin 180 – (A + B)
sin C = sin (A + B)
sin C = sin A cos B + cos A sin B
sin C = 3/5. 5/13 + 4/5. 12/13
sin C = 15/65 + 48/65
sin C = 63/65