The angle of repose for dry shelled corn is 23 degrees or a tangent of .42
The tangent of 75 degrees is: 3.7320507852401
the tangent of 60 degrees is 1.7321
The tangent of 89 degrees is: 57.3
Tangent of 30 degrees is 0.5770.577
Tangent is 0.5317
The question seems to be incomplete!
Tangent = 0.5
The tangent of 0.47 radians is about 0.508. The tangent of 0.47 degrees is about 0.00820.
The inverse tangent is 0.83448691252602 degrees.
Tangent of theta = Y/X, or opposite the angle/the adjacent of angle. So; Tangent of 42 degrees = height/80' 80' tan 42 = height = 72 feet ( you might want to subtract that 4.5 foot eye height )
45 degrees