MathDB
Triangle

Source:

December 6, 2005
geometryincenterratioinradiusAMCAIMEnumber theory

Problem Statement

Triangle ABCABC has AB=21AB=21, AC=22AC=22, and BC=20BC=20. Points DD and EE are located on AB\overline{AB} and AC\overline{AC}, respectively, such that DE\overline{DE} is parallel to BC\overline{BC} and contains the center of the inscribed circle of triangle ABCABC. Then DE=m/nDE=m/n, where mm and nn are relatively prime positive integers. Find m+nm+n.