In triangle $ \bigtriangleup ABC$, the known sides are: $AB=5$, $BC=6$ and $AC=7$. A circle passes through points $A$ and $C$, crosses straight lines $BA$ and $BC$ at points $K$ and $L$, which is non-vertex angle, respectively. Segment KL As to the incircle of the triangle ABC.
Please find the length of the segment $KL$, and show me how to.