concyclic projections of a point on faces of pyramid 1989 Kyiv City MO 10.5
Source:
July 17, 2021
geometry3D geometrypyramidConcyclic
Problem Statement
The base of the quadrangular pyramid is a quadrilateral , the diagonals of which are perpendicular. The apex of the pyramid is projected at intersection point of the diagonals of the base. Prove that the feet of the perpendiculars drawn from point to the side faces of the pyramid lie on one circle.