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inverse of isosceles criterion? external angle bisectors, circumcircle related

Source: 2008 Oral Moscow Geometry Olympiad grades 8-9 p2

October 13, 2020
geometryangle bisectorcircumcircleisosceles

Problem Statement

In a certain triangle, the bisectors of the two interior angles were extended to the intersection with the circumscribed circle and two equal chords were obtained. Is it true that the triangle is isosceles?