Question 1027630
<pre>
You can't use the cosine or the sine because they involve
the hypotenuse.  You neither know the hypotenuse nor is
the hypotenuse the side that you want to find. 

You know the angle and the adjacent side only, and you want 
to find the opposite x. So you use whichever one of the three 
main trig ratios that has both the side given 51m and the side
you want to find as a numerator and denominator.  That is the 
tangent because tangent = opposite/adjacent.    

Again, always pick the trig ratio that has both the known side 
and the side you want to find as a numerator and denominator.  

Edwin</pre>