Answer
$F = 425$
Work Step by Step
$F = \frac{0.6W~sin(\theta+90^{\circ})}{sin~12^{\circ}}$
Let $W = 170~lb$ and let $\theta = 30^{\circ}$
$F = \frac{(0.6)(170)~sin(30^{\circ}+90^{\circ})}{sin~12^{\circ}}$
$F = \frac{102~sin(120^{\circ})}{sin~12^{\circ}}$
$F = 425$
