FB page of Thiago Durado, https://www.facebook.com/photo/?fbid=1023025149998443&set=a.304452958522336

 

aops, https://artofproblemsolving.com/community/c6t48f6h3599961_prove_that_two_angles_are_equal_on_a_rectangle

 

Triple angle lemma

 

FB page of Nelson Tunala, https://www.facebook.com/photo/?fbid=10031253546943032&set=a.542610499140765

 

Geometria Super Top, https://www.facebook.com/photo?fbid=9331301963636165&set=gm.1985486205555072&idorvanity=830782544358783

 

aops, https://artofproblemsolving.com/community/c6t48f6h3597307_geometry_problem

 

aops, https://artofproblemsolving.com/community/c4t48f4h3596137_difficult_triangle_angle_chasing

 

https://www.facebook.com/photo?fbid=122242400462203033&set=gm.1983140779122948&idorvanity=830782544358783

 

Trazo Geometrico Maldito, Alexsander AC, https://www.facebook.com/photo?fbid=10220811120707581&set=gm.1826856031159813&idorvanity=715291165649644

 

FB, Trazo Geometrico Maldito, https://www.facebook.com/photo/?fbid=1609031989960973&set=a.1172983803565796, problem 231

 

FB page of Hasan Ata, https://www.facebook.com/photo?fbid=8697671933649093&set=a.712949622121404

 

aops, https://artofproblemsolving.com/community/c4t48f4h3579684_a_geometry_problem_to_calculate_the_size_of_an_angle

 

aops, https://artofproblemsolving.com/community/c4t48f4h3585809_geometry

 

Full solution of https://www.facebook.com/photo/?fbid=1899709203808549&set=a.148394885606665

 Thanking to Alin Cretu, 

Unfinished solution of a problem by Thanos Kalogerakis, https://www.facebook.com/photo?fbid=1899709203808549&set=a.148394885606665