Really need with this question don't know how to do it.

We know that the height of the flagpole is 5.5 plus the height that is left, so we will call the height x + 5.5.

Now we now that the angle of elevation is 23 and the side of the bottom of "the triangle" is 30. So we can conclude that tan 23=(x/30)

x= 30tan23
The height would be 30tan23  + 5.5 which is 18.23 ft.