One of my old problems

 For <BAC=20 I shall post my synthetic solution later on

Problem: https://artofproblemsolving.com/community/c4t48f4h3352797_an_alright_geo_problem

 

Naibe Oliveira, Training Geometry Olympiad

 

https://www.facebook.com/groups/970715314297475/permalink/1206897867345884

 With my son paramount observation

Geometria (solo trazos), Razan Al Haddad, https://www.facebook.com/photo?fbid=431799229393013&set=gm.1807980529693318&idorvanity=179005525924168

 

https://www.facebook.com/photo/?fbid=6785852008183973&set=pcb.6785868758182298, prob. 6

Classical mathematics, https://www.facebook.com/photo/?fbid=8411977608816959&set=gm.1402771007057882&idorvanity=340992303235763

 A fast solution