48 cm → lungimea cutiei ( L )
48 cm - 19 cm = 29 cm → latimea
29 cm - 9 cm = 20 cm → inaltimea
Paralelipipedul are 12 muchii: 4 lungimi, 4 latimi si 4 inaltimi
4 × 48 cm + 4 × 29 cm + 4 × 20 cm = 192 cm + 116 cm + 80 cm = 388 cm → suma lungimilor muchiilor cutiei