theta = 15° 30', The distance (horizontal) is simply 120 * tan (90 - theta)?

Question

theta = 15° 30'
The distance (horizontal) is simply
120 * tan (90 - theta)

show me the solution

Answer 1

theta = 15° 30'

then 90 - theta = 90 - 15° 30'

15° 30' = 15.5°, as 30' = 0.5°

tan(90 - 15.5) = tan(74.5)

distance = 120*tan(74.5)

distance = 120*3.606 = 432.71
.

Answer 2

15° 30' = 15.5°
tan(90° - 15.5°) = 1/tan(15.5°)
120/tan(15.5°) = 432.7060