A plateau height is
in height.
The angle of elevation is to the top of the plateau 

Observe the figure :
and
.
For a right angle triangle :
\Let
and
.
Consider the trigonometric functions:
and
.
Substitute
,
and 



Therefore,
.
Find distance between
and
.
is adjacent side of the right angle triangle.
So,
.
Substitute
,
and
.


Distance from base to plateau is
.
Distance from base to plateau is
.