Math Forum :: View topic – trapezoid 4월 6, 2005 admin Author Message mmrproblem Joined: 05 Nov 2004Posts: 16 Posted: Wed Nov 24, 2004 5:07 am Post subject: trapezoid Let ABCD be an isosceles trapezoid,AB=CD and AD//BC.Let E be a point on [BC ray such that E out of [BC] line segment and EC