Prove that there exist(adsbygoogle = window.adsbygoogle || []).push({});

(a) 5 points in the plane so that among all the triangles with vertices among these points there are 8 right-angled ones;

(b) 64 points in the plane so that among all the triangles with vertices among these points there are at least 2005 right-angled ones.

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# Prove that

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