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

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