MathDB
difference of angles wanted, equal angles(2016 Novosibirsk Oral Geo Oly 8-9 p2)

Source:

April 26, 2021
geometryangles

Problem Statement

Bisector of one angle of triangle ABCABC is equal to the bisector of its external angle at the same vertex (see figure). Find the difference between the other two angles of the triangle. https://cdn.artofproblemsolving.com/attachments/c/3/d2efeb65544c45a15acccab8db05c8314eb5f2.png