Problem

Source: V.A. Yasinsky Geometry Olympiad 2017 advanced X-XI p3 [Ukranie]

Tags: geometry, Chords, angle bisector



In a circle, let $AB$ and $BC$ be chords , with $AB =\sqrt3, BC =3\sqrt3, \angle ABC =60^o$. Find the length of the circle chord that divides angle $ \angle ABC$ in half.