MathDB

10

Part of 2008 Sharygin Geometry Olympiad

Problems(1)

crcumscribed quadrilateral

Source: Sharygin contest 2008. The correspondence round. Problem 10

9/3/2008
(A.Zaslavsky, 9--10) Quadrilateral ABCD ABCD is circumscribed arounda circle with center I I. Prove that the projections of points B B and D D to the lines IA IA and IC IC lie on a single circle.
geometryangle bisectorgeometry proposed