Answer:
D
Explanation:
The answer is the side opposite / hypotenuse.
Definitions
The side opposite is the side which is not connected directly with angle (A). So it is the line that is 24 units long.
The hypotenuse is the longest line of a right triangle. It is opposite the right angle. It is 30 in this case.
Answer
Sin-1(24)/30
You haven't got an answer that is correct.
Tan-1(24/18) would work
The answer that is given that will work is cos-1(18/30)