MathDB
Nice Conditions!

Source: Czech-Slovak Match 1996

September 14, 2004
geometrygeometry solved

Problem Statement

The points EE and DD lie in the interior of sides ACAC and BCBC, respectively, of a triangle ABCABC. Let FF be the intersection of the lines ADAD and BEBE.Show that the area of the traingles ABCABC and ABFABF satisfies: SABCSABF=ACAE+BCBD1 \frac{S_{ABC}}{S_{ABF}} = \frac{\mid{AC}\mid}{\mid{AE} \mid} + \frac{\mid{BC}\mid}{\mid{BD}\mid} - 1.