MathDB
<BXD = <CY D if AXBCY is cyclic

Source: 2022 Dutch BxMO TST p2

December 3, 2022
geometryequal anglesangles

Problem Statement

Let ABCABC be an acute triangle, and let DD be the foot of the altitude from AA. The circle with centre AA passing through DD intersects the circumcircle of triangle ABCABC in XX and YY , in such a way that the order of the points on this circumcircle is: A,X,B,C,YA, X, B, C, Y . Show that ∠BXD=∠CYD\angle BXD = \angle CYD.
Back to ProblemsView on AoPS