IMO Shortlist 2018 problem G7
Kvaliteta:
Avg: 0,0Težina:
Avg: 8,5Let be the circumcentre, and
be the circumcircle of an acute-angled triangle
. Let
be an arbitrary point on
, distinct from
,
,
, and their antipodes in
. Denote the circumcentres of the triangles
,
, and
by
,
, and
, respectively. The lines
,
,
perpendicular to
,
, and
pass through
,
, and
, respectively. Prove that the circumcircle of triangle formed by
,
, and
is tangent to the line
.
Izvor: https://www.imo-official.org/problems/IMO2018SL.pdf