In all right triangles, the ratio between a leg and the hypothenuse is the sine of the angle opposite to the leg.
So, in your case, we have

In order to find XY, we have

So, the ratio for the sine is

Answer:
A
Step-by-step explanation:
12*3 = 36 = A
Angle OPM and Angle LMK
When angles are corresponding, they're essentially on the same side. It's sort of hard to explain, so I'll attach a drawing. The one on the left with the check mark is a corresponding angle, and the one on the right with the X is a same-side angle. Essentially, corresponding angles are on the same side and are also equal, unlike same-side angles, which are supplementary angles.
Let me know if you don't understand my explanation.
-T.B.
http://www.stgeorges.co.uk/blog/how-can-i-describe-a-graph-ielts-writing-task-part-1-business-english