NOTE: This very difficult problem of elementary geometry has an ancient Japanese source (See “Sacred Mathematics: Japanese Temple Geometry”. Princeton University Press, 2008, by F. Hidetoshi & T. Rothman). It was given by F. Hidetoshi to the Spanish international journal “Revista de la O. I. M.” for publication. I was the only that comes to a complete solution and two Spaniards and a Chilean gave partial solutions. I would love to see another answer but do not know if you can post it here with that precedent.

NOTE: This very difficult problem of elementary geometry has an ancient Japanese source (See “Sacred Mathematics: Japanese Temple Geometry”. Princeton University Press, 2008, by F. Hidetoshi & T. Rothman). It was given by F. Hidetoshi to the Spanish international journal “Revista de la O. I. M.” for publication. I was the only one to submit a complete solution, while two Spaniards and a Chilean gave partial solutions. I would love to see another answer but do not know if you can post it here with that precedent.