From h a point A that is 10 meters abov level ground, the angle of elevation of the top a building is 42 degrees and the angle of depression of the base of the building is 8 degrees approximate the height of the building

Answer 1

Let the building height be Y
Let the horizontal distance to the building be h.

h tan 42 = a
h tan 8 = b

Y = a + b = h (tan42,+ tan 8)

For the value of h, use
h tan 8 = 10 m