MathDB
Determine y - ISL 1986 p3

Source:

August 31, 2010
number theoryDiophantine equationgeometryalgebraPythagorean TheoremIMO Shortlist

Problem Statement

Let A,BA, B, and CC be three points on the edge of a circular chord such that BB is due west of CC and ABCABC is an equilateral triangle whose side is 8686 meters long. A boy swam from AA directly toward BB. After covering a distance of xx meters, he turned and swam westward, reaching the shore after covering a distance of yy meters. If xx and yy are both positive integers, determine y.y.