Answer
$F'=161N$
$F_R=257N$
$\phi=163^{\circ}$
Work Step by Step
$c=\sqrt{a^2+b^2-2*a*b*\cos(C)}$
$F'=\sqrt{300^2+200^2-2*300*200*\cos(30^{\circ})}$
$F'=161.48N$
$\sin30^{\circ} / 161.48 = \sin \theta'/ 200$
$\theta'= 38.26^{\circ}$
$c=\sqrt{a^2+b^2-2*a*b*\cos(C)}$
$F_R=\sqrt{400^2+161.48^2-2*400*161.48*\cos(21.74^{\circ})}$
$F_R=257N$
$\sin 21.74^{\circ} / 257.05 = \sin \theta/ 161.48$
$\theta= 13.45^{\circ}$
$\phi=90^{\circ}+60^{\circ}+13.45^{\circ}=163^{\circ}$
