9

Part of 2001 Baltic Way

Problems(1)

The locus of P with supplementary angles condition

Source: Baltic Way 2001

Given a rhombus

ABCD

, find the locus of the points

P

lying inside the rhombus and satisfying

\angle APD+\angle BPC=180^{\circ}

geometryrhombusparallelogramcircumcircleconicshyperbolacyclic quadrilateral