\begin{aligned} & \text { [The inscribed angle is half the central angle] } \\ & {[\quad \text { Symmetry helps solve the problem. }]}\end{aligned}

Point $X$ is located on the diameter $A B$ of a circle with radius $R$. Points $K$ and $N$ lie on the circle in the same half-plane relative to $A B$,

and $\angle K X A=\angle N X B=60^{\circ}$. Find the length of the segment $K N$.