MathDB

4

Part of 2018 Polish Junior MO Second Round

Problems(1)

Equality of angles in trapezoid

Source: XIII Polish Junior MO 2018 Second Round - Problem 4

4/24/2018
Let ABCDABCD be a trapezoid with bases ABAB and CDCD. Points PP and QQ lie on diagonals ACAC and BDBD, respectively and ∠APD=∠BQC\angle APD = \angle BQC. Prove that ∠AQD=∠BPC\angle AQD = \angle BPC.
geometrytrapezoidPlane GeometryPoland