MathDB
each of 4 quads inside a unit area convex quad has area < 3/8

Source: Netherlands - Dutch NMO 1974, year 1974-75 (also named as 1975 -1) p1

January 27, 2023
geometrycombinatorial geometryareasgeometric inequality

Problem Statement

A convex quadrilateral with area 11 is divided into four quadrilaterals divided by connecting the midpoints of the opposite sides. Prove that each of those four quadrilaterals has area <38< \frac38.