IMO Shortlist 1989 problem 1
Dodao/la:
arhiva2. travnja 2012. 
is a triangle, the bisector of angle

meets the circumcircle of triangle

in

, points

and

are defined similarly. Let

meet the lines that bisect the two external angles at

and

in

. Define

and

similarly. Prove that the area of triangle

area of hexagon

area of triangle

.
%V0
$ABC$ is a triangle, the bisector of angle $A$ meets the circumcircle of triangle $ABC$ in $A_1$, points $B_1$ and $C_1$ are defined similarly. Let $AA_1$ meet the lines that bisect the two external angles at $B$ and $C$ in $A_0$. Define $B_0$ and $C_0$ similarly. Prove that the area of triangle $A_0B_0C_0 = 2 \cdot$ area of hexagon $AC_1BA_1CB_1 \geq 4 \cdot$ area of triangle $ABC$.
Izvor: Međunarodna matematička olimpijada, shortlist 1989