Solution 4.7b
From Mechanics
\displaystyle \begin{align} & \mathbf{F}1= & =86\textrm{.}6\mathbf{i}+50\mathbf{j}\ \text{N}\\ \end{align}
\displaystyle \begin{align} & \mathbf{F}2= & =-30\textrm{.}8\mathbf{i}+84\textrm{.}6\mathbf{j} \ \text{N}\\ \end{align}
\displaystyle \begin{align} & \mathbf{F}3= & =-80\mathbf{j}\ \text{N}\\ \end{align}