Question

Which of the following statements is true?

a. sin 18° = cos 720
b. sin 55° = cos 55°
C. sin 72° = cos 18°
d. Both a and c.

Answer 1

C is the right answer to this

Answer 2

C

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)