XY is the height of the tower (use X as the base)
AB is a 50 m baseline, some distance away from the tower.
Angle XAY = 42.6 (which is the vertical angle from ground level to the top of the tower)
Angle XAB = 60 (and is the horizontal angle between the line segment AX and AB
Angle ABX = 81.65 (the horizontal angle between the line segment AB and BX.
Find Angle AXB = 180 degrees - 60 degrees - 81.65 degrees = 38.35 degrees
Use law of sines to find distance AX:
sin 38.35/50 = sin 81.65 / AX and AX = 79.7 m
Use AX and the vertical angle to find the height of the tower:
42.6 degrees is the vertical angle between line AX and XY
Tan 42.6 = XY/79.7
XY, the height of the tower is 73.3 m Answer