Let the angle of elevation be θ.
We have a right angled triangle with an opposite of 300.5 ft. (306 - 5.5) and an adjacent of 400 ft. Recalling SOH CAH TOA, tanθ = O/A.
tan(θ) = 300.5/400.
θ = tan^-1(300.5/400).
θ = 36.9°.
The answer is d.61. 66+7=73. 13+8=21. 52+9=61. 10+10=20
All but the last one I think but don't quote me