Find $x$ $$\sin60 \sin30 \sin x=\sin50 \sin20 \sin(20-x)$$
$\frac{\sin(20^\circ-x)}{\sin x} = \cos 20^\circ-\sin20^\circ\cdot \cot x$, so we can easily find $x$. But you write Cheva theorem, probably, there exists a geometric solution.
Find $x$ $$\sin60 \sin30 \sin x=\sin50 \sin20 \sin(20-x)$$
$\frac{\sin(20^\circ-x)}{\sin x} = \cos 20^\circ-\sin20^\circ\cdot \cot x$, so we can easily find $x$. But you write Cheva theorem, probably, there exists a geometric solution.