now... notice the picture
now, how many units in the adjacent side,
and how many in the opposite side
let us notice is a right-triangle, thus
[tex]\bf tan(\theta)=\cfrac{opposite}{adjacent}\implies \theta=tan^{-1}\left( \cfrac{opposite}{adjacent} \right)\\\\
-----------------------------\\\\
thus
\\\\
tan(N)=tan(\theta)=\cfrac{opposite}{adjacent}\implies \measuredangle N==tan^{-1}\left( \cfrac{opposite}{adjacent} \right)[/tex]
when taking the tangent, make sure your calculator is in Degree mode, since you're asked to give angle N in degrees
