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<A'B'C'=? angle bisectors, <B=120^o (2020 Novosibirsk Oral Geo Oly 7.6)

Source:

April 27, 2021
geometryangle bisectorangles

Problem Statement

Angle bisectors AA,BBAA', BB'and CCCC' are drawn in triangle ABCABC with angle B=120o\angle B= 120^o. Find ABC\angle A'B'C'.