MathDB
points definded by projections of intersections of tangents on sides

Source: Sharygin Geometry Olympiad 2017 First Round P16 grades 9-11

July 22, 2018
geometryconcurrencyconcurrenttangent

Problem Statement

The tangents to the circumcircle of triangle ABCABC at AA and BB meet at point DD. The circle passing through the projections of DD to BC,CA,ABBC, CA, AB, meet ABAB for the second time at point C′C'. Points A′,B′A', B' are defined similarly. Prove that AA′,BB′,CC′AA', BB', CC' concur.
Back to ProblemsView on AoPS