IMO 1983 LL BRA11
A boy at point A wants to get water at a circular lake and
IMO 1983 LL BRA11
Origin: BRA
Problem
A boy at point A wants to get water at a circular lake and carry it to point B. Find the point C on the lake such that the distance walked by the boy is the shortest possible given that the line AB and the lake are exterior to each other.