Răspunsuri

2014-10-28T18:42:07+02:00
(56/2):4=7 cm are lățimea, iar lungimea 3x7=21 cm
2014-10-28T18:45:30+02:00
L = 3l => (L + l) × 2 = 56 => (3l + l) × 2 = 56 => 4l × 2 = 56 => 8l = 56/:8 => l = 7 cm (lățimea) => L = 3 × 7 = 21 cm (lungimea)