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geometry(iranian geometry olympiad 2017)
Posted: Sun Jan 28, 2018 10:59 pm
by abrarfiaz
4. P1,P2,...,P100 are 100 points on the plane, no three of them are collinear. For each three points, call their triangle clockwise if the increasing order of them is in clockwise order. Can the number of clockwise triangles be exactly 2017?
help me solving the problem
Re: geometry(iranian geometry olympiad 2017)
Posted: Sun Feb 04, 2018 2:54 am
by ahmedittihad
What help do you need?
Re: geometry(iranian geometry olympiad 2017)
Posted: Mon Feb 05, 2018 7:54 pm
by abrarfiaz
I am being unable of understanding the main concept of the problem. Truly to say ,can't understand the problem. I would be grateful if you do help me
Re: geometry(iranian geometry olympiad 2017)
Posted: Tue Feb 06, 2018 1:14 pm
by ahmedittihad
Okay so you're having difficulty in understanding what clockwise is. In the picture $ABC$ is clockwise and $A_1B_1C_1$ is counterclockwise.
Re: geometry(iranian geometry olympiad 2017)
Posted: Tue Feb 20, 2018 1:57 pm
by samiul_samin
abrarfiaz wrote: ↑Mon Feb 05, 2018 7:54 pm
I am being unable of understanding the main concept of the problem. Truly to say ,can't understand the problem. I would be grateful if you do help me
Sketch of the solution