MathDB

24

Part of 2009 Sharygin Geometry Olympiad

Problems(1)

A sphere is inscribed into a quadrangular pyramid

Source: I.F.Sharygin contest 2009 - Correspondence round - Problem 24

5/31/2009
A sphere is inscribed into a quadrangular pyramid. The point of contact of the sphere with the base of the pyramid is projected to the edges of the base. Prove that these projections are concyclic.
geometry3D geometryspherepyramidgeometry proposed