What's the angle of elevation from the bench to the top of this building?​

If 120 ft is the height of the building,
tan(40deg) = height of building/ perpendicular distance from base of tree to building = 120/x
—> x= 120/tan(40deg)
Distance from bench to building = [120/tan(40deg)]- 50 (calculate this) ——(1)
tan(angle of elevation) = height of building/ distance from bench to building = 120/(answer from (1))
angle of elevation = arctan( 120/answer from (1) ) (calculate this too)