Answer
$$
\begin{aligned}
& F=798 \mathrm{lb} \\
& \theta=67.9^{\circ} \\
& x=6.57 \mathrm{ft}
\end{aligned}
$$
Work Step by Step
$$
\pm \Sigma F_{R_x}=\Sigma F_x ; \quad F_{R_{\mathrm{s}}}=-500\left(\frac{4}{5}\right)+260\left(\frac{5}{13}\right)=-300 \mathrm{lb}=300 \mathrm{lb} \leftarrow
$$
$$
+\uparrow F_{R_y}=\Sigma F_y \quad F_{R_y}=-500\left(\frac{3}{5}\right)-200-260\left(\frac{12}{13}\right)=-740 \mathrm{lb}=740 \mathrm{lb} \downarrow
$$
$$
F=\sqrt{(-300)^2+(-740)^2}=798 \mathrm{lb}
$$
$$
\theta=\tan ^{-1}\left(\frac{740}{300}\right)=67.9^{\circ}
$$
$$
\begin{array}{cl}
↺+M_{R B}=\Sigma M_B ; \quad & 740(x)=500\left(\frac{3}{5}\right)(9)+200(6)+260\left(\frac{12}{13}\right)(4) \\
& x=6.57 \mathrm{ft}
\end{array}
$$
