Explanation:
Step 1: Find the answer
To find sine, that means we need to find the y-value where it equals √3/2.
If you know the unit circle, you know that the long side is √3/2 and the short side is 1/2. So... in order to have the long side to be a y-value, that means that we need to have a long vertical triangle. The angle that will fit this will be 60 degrees.
On you calculator, you should have a sin and you just type in something like this: sin(60) and it should give you √3/2.
Answer: Option A, 60