IMO 1976 LL NET27

In a plane three points P, Q, R, not on a line, are given. Let

IMO 1976 LL NET27

Origin: NET

Problem

In a plane three points P, Q, R, not on a line, are given. Let k, l, m be positive numbers. Construct a triangle ABC whose sides pass through P, Q, and R such that P divides the segment AB in the ratio 1 : k, Q divides the segment BC in the ratio 1 : l, and R divides the segment CA in the ratio 1 : m.