I'm currently learning this in math...but I have no clue on how to start the question! This is a 3D trigonometry question so I know it's best to always draw a diagram first. Problem is, I don't how where to begin

The Crows-nest of a yacht is 50.0 m above water level. The angle of depression from the crows nest to a buoy due west of the boat is 40/degree/. The angle of depression from another buoy S70/degress/W of the yacht is 34/degrees/. How far apart are the buoys?

The answer is 27.3m...but how did they do it?