MathDB

2007.4

Part of Indonesia Regional MO OSP SMA - geometry

Problems(1)

DE + DF <= BC , 3 altitudes

Source: 2007 Indonedia MO Province P2 q4 OSP

12/11/2020
In acute triangles ABCABC, AD,BE,CFAD, BE ,CF are altitudes, with D,E,FD, E, F on the sides BC,CA,ABBC, CA, AB, respectively. Prove that DE+DF≤BCDE + DF \le BC
geometrygeometric inequalityaltitudes