Perimtrul=2 ori (lungime+latime). Lungime= 2 ori latime+12 din astea doua=> 5160= 2 ori( 2 ori latime+12+latime)=> 5160= 2 ori(3 latime+12)=> 5610=6ori latime+24=> 5160-24=6 ori latime=> 5136=6 ori larime=> latime=5136:6=> latime= 856 m. Acum avem lungime=2 ori latime+12=> lungime=2 ori 856+12=> lungime=1724m
