Y by 606234, Math_olympics, justJen, samrocksnature, megarnie, CrazyInMath, Rounak_iitr, GeoKing, Funcshun840
Let
,
,
,
be four points such that no three are collinear and
is not the orthocenter of
. Let
,
,
be the orthocenters of
,
,
, respectively. Suppose that the lines
,
,
are pairwise distinct and are concurrent. Show that the four points
,
,
,
lie on a circle.
Andrew Gu



















Andrew Gu
This post has been edited 2 times. Last edited by v_Enhance, Mar 1, 2021, 5:21 PM