MathDB
Archimedes broken chord theorem

Source: ISI(BS) 2006 #4

June 13, 2012
geometryangle bisectorgeometry proposed

Problem Statement

In the figure below, EE is the midpoint of the arc ABECABEC and the segment EDED is perpendicular to the chord BCBC at DD. If the length of the chord ABAB is l1l_1, and that of the segment BDBD is l2l_2, determine the length of DCDC in terms of l1,l2l_1, l_2. [asy] unitsize(1 cm); pair A=2dir(240),B=2dir(190),C=2dir(30),E=2dir(135),D=foot(E,B,C); draw(circle((0,0),2)); draw(A--B--C); draw(E--D); draw(rightanglemark(C,D,E,8)); label("AA",A,.5A); label("BB",B,.5B); label("CC",C,.5C); label("EE",E,.5E); label("DD",D,dir(-60)); [/asy]