1. Two forces F₁ and F₂ act on a particle, where  ${F}_{1}=5i-3j$newtons and ${F}_{2}=xi+yj$ newtons.

The resultant force R acting on the particle is given by $R={F}_{1}+{F}_{2}$, and acts in a direction parallel to the vector $(-i-3j)$.

Find the angle between R and the vector j, giving your answer in degrees correct to 2 decimal places.