Respuesta :

we know that
tan ∅=opposite side angle ∅/adjacent side angle ∅

in this problem
opposite side angle ∅=150 ft
adjacent side angle ∅=120 ft
∅=angle of elevation
so
tan ∅=150/120--------> 1.25
∅=arc tan(1.25)---------> ∅=51.34°

the answer is
51.34°