From Mechanics

Resultant force \displaystyle =80\textrm{.}9\mathbf{i}-11\textrm{.}3\mathbf{j}\ \text{N}

Thus

\displaystyle \tan \alpha =\frac{-11\textrm{.}3}{80\textrm{.}9}=-0\textrm{.}14

giving

\displaystyle \alpha =-8\textrm{.}0{}^\circ

As the vector is in the fourth quadrant