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Geometric inequality with a,b,c,r

Source:

November 1, 2010
inequalitiesgeometryinradiusperimetergeometry unsolved

Problem Statement

If a,b,ca,b,c are the sides of a triangle and rr the inradius of the triangle, prove that 1a2+1b2+1c214r2\frac{1}{a^2}+\frac{1}{b^2}+\frac{1}{c^2}\le \frac{1}{4r^2}