https://artofproblemsolving.com/community/c6h616123p3670325

 This is my synthetic proof to the subject problem:

https://artofproblemsolving.com/community/c6t48f6h3304019

 

https://artofproblemsolving.com/community/c4t48f4h3294054_geometry7

 Attached, my solution... Ooops! So far it's wrong!

https://www.facebook.com/photo?fbid=418692704036999&set=gm.1648363175934045&idorvanity=830782544358783

 

2 problems, https://artofproblemsolving.com/community/c4t48f4h3300850_geometry

 See attached, synthetic solutions for the 2 problems posted there

Binh Luc, Peru Geometrico, https://www.facebook.com/photo/?fbid=10228034844329488&set=gm.7197648463681318&idorvanity=400828670030032

 See the drawing and explanation attached.

Best regards.

Training Geometry Olympiad, Naibe Oliveira, https://www.facebook.com/photo?fbid=931182985160309&set=gm.1085609866032659&idorvanity=293155508611436

 My solution attached: