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Let's play with angles

Source: Greece Junior National Olympiad 2022, Problem 2

February 26, 2022
geometry

Problem Statement

Let ABCABC be an isosceles triangle, and point DD in its interior such that DB^C=30,DB^A=50,DC^B=55D \hat{B} C=30^\circ, D \hat{B}A=50^\circ, D \hat{C}B=55^\circ
(a) Prove that B^=C^=80\hat B=\hat C=80^\circ. (b) Find the measure of the angle DA^CD \hat{A} C.