MathDB

1

Part of 2018 Serbia National Math Olympiad

Problems(1)

Angle PDE

Source: Serbia MO 2018 P1

4/2/2018
Let △ABC\triangle ABC be a triangle with incenter II. Points PP and QQ are chosen on segmets BIBI and CICI such that 2∠PAQ=∠BAC2\angle PAQ=\angle BAC. If DD is the touch point of incircle and side BCBC prove that ∠PDQ=90\angle PDQ=90.
geometryincentermoving pointsSerbiaTriangle