MathDB
Analytic Geometry

Source: AIME 2 2000 #11

December 9, 2005
geometryanalytic geometrytrapezoidgraphing linesslopenumber theoryrelatively prime

Problem Statement

The coordinates of the vertices of isosceles trapezoid ABCDABCD are all integers, with A=(20,100)A=(20,100) and D=(21,107).D=(21,107). The trapezoid has no horizontal or vertical sides, and AB\overline{AB} and CD\overline{CD} are the only parallel sides. The sum o f the absolute values of all possible slopes for AB\overline{AB} is m/n,m/n, where mm and nn are relatively prime positive integers. Find m+n.m+n.