Question 93274
An airplane is flying 8,000 feet above the level ground.  The angle of depression from the plane to the base of the tree is 16.4 degrees.  How far horizontally must the plane fly to be directly above the tree?  
-------------
Draw the picture;label the parts of the triangle
---------------------.
The angle of elevation of the plane from the ground is the same 
as the angle of depression of the tree from the plane.
Let horizontal distance from the plane to the tree be "x"
------------------
EQUATION:
tan(16.4 degrees) = 6000/x
x  = 6000/(tan(16.4))
x = 20386.25 ft.
===================
Cheers,
Stan H.