first draw a diagram - a right-angled triangle consising of the tower, the ground and a line at 59 degrees from the tower to the ground. work out the hypotenuse of this triangle using trig. this is the distance to W
then another triangle, same as before, but with an angle of 73 degrees, and call this distance S
by pythagoras, the distance is given by d² = S² + W². if you want to draw a diagram, its a right-angled triangle, with the man at the right-angle and the two non-hypotenuse sides of lengths S and W.
of course you could draw all these triangles in one, if you are good at 3d projections.