It presents some nice ideas, in my opinion, to solve types of really difficult problems in angle calculus, all full of thorns

Cuprins

1 Useful theorems / lemmas
2 New idea, two problems, one solution
3 Incenter, circumcenter, excenter
4 Mustafa Yagci triangle
5 Triple angle lemma, double angle lemma
6 Lemma, important
7 Pantalon ` theorem, isogonal conjugate points
8 Langley triangle properties
9 Case of triangles congruency
10 Various methods to solve problems
11 Problems to be solved