<Tri-2026-2316>, hint

 

<Tri-2026-2316 >, general, incenter

<South Africa Contest 1995>

<Tri-2026-2315>, hint

Suppose <ACB>90 ,<BAC=<BDA.<BAC

E is the circumcenter of triangle ACD, and <CAE=90-<BDA=90-<BAC

Hence <BAE=<BAC+<CAE=90

<Tri-2026-2315>, general, angle

South Africa Contest 1995>

 

<Tri-2026-2314>, hint