Given
![100](/media/m/c/c/c/ccc0563efabf7c1a3d81b0dc63f5b627.png)
coplanar points, no three collinear, prove that at most
![70\%](/media/m/0/7/6/07670eec99cb122593a139f06bc287f1.png)
of the triangles formed by the points have all angles acute.
%V0
Given $100$ coplanar points, no three collinear, prove that at most $70\%$ of the triangles formed by the points have all angles acute.