<Tri-2026-2797>, general, orthocenter

<Swiss MO 2007>

 

 <Qua-2026-834>, hint

<Qua-2026-834>, general, cyclic

<Swiss MO 2006>

 

<Cir-2026-807>, hint

 

<Cir-2026-807>, tangent

<Swiss MO 2006>