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Prove this inequality for any point in the plane of triangle

Source: 2009 Jozsef Wildt International Math Competition

April 27, 2020
Trianglegeometryinequalities

Problem Statement

If KK, LL, MM denote the midpoints of the sides ABAB, BCBC, CACA in triangle ABC\triangle ABC, then for all PP in the plane of triangle ABC\triangle ABC, we have ABPK+BCPL+CAPMABBCCA4PKPLPM\frac{AB}{PK}+\frac{BC}{PL}+\frac{CA}{PM} \geq \frac{AB\cdot BC \cdot CA}{4\cdot PK\cdot PL\cdot PM}