Answer:
  h ’= 0.6963 m
this is the height of the part of the post it supports.
Explanation:
For this exercise we can use the trigonometric relationships
Let's start by finding the vertical component of the height of the pole
       cos 30 = x / L
       x = L cos 30
       x = 6 cps 30
       x = 5.196 m
with this length, the post has the same height as the building, so there are
        Aₓ = L -x
        Δx = 6 -5.196
        Δx = 0.804 ft
the height of this section is
        cos 30 = h ’/ Dx
        h ’= 0.804 cos30
        h ’= 0.6963 m
this is the height of the part of the post it supports.