Answer:
C
Step-by-step explanation:
A) not true. Sin A = some decimal
Cos 720 = 1
D) That means that d is not true either. not true
B) Sin55 = cos55 is not true either only sin(45) = cos(45) is true. So B is not true.
That leaves C. I think if you check it, you'll find it is right. sin(A) = cos(90 - A)
