Geometry ( IMO 1960 )

[Mohammed 23]

I have attached the question and it’s solution . I m facing a slight problem understanding the highlighted part of the solution
Could someone please explain that part only ?

 

[Deleted member 4993]

I have attached the question and it’s solution . I m facing a slight problem understanding the highlighted part of the solution
Could someone please explain that part only ?

Did you draw sketch with the points A, B, C, P, Q & R?

Please show that sketch and somebody can guide you through the answer.

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

READ BEFORE POSTING​

Please share your work/thoughts about these problems.

 

[Mohammed 23]

I did till this step , I don’t know the continuation