MathDB
Turkey Junior Olympiad 2006, Part II - P1

Source:

January 20, 2013
geometrytrapezoid

Problem Statement

Let ABCDABCD be a trapezoid such that ADBCAD\parallel BC. The interior angle bisectors of the corners AA and BB meet on [DC][DC]. If BC=9|BC|=9 and AD=4|AD|=4, find AB|AB|.