IMO 1966 LL BUL22

Origin: BUL

Problem

Assume that two parallelograms P, P ′ of equal areas have sides a, b and a′, b′ respectively such that a′ \leqa \leqb \leqb′ and a segment of length b′ can be placed inside P. Prove that P and P ′ can be partitioned into four pairwise congruent parts.