P = 2×(L+l) = 104,8 cm L+l = 104,8:2 L + l = 52,4 l = L - 12,61 L + L - 12,61 = 52,4 2×L = 52,4 + 12,61 2×L = 65,01 L = 65,01:2 L = 32,505 cm (Lungimea) l = 32,505-12,61 l = 19,895 cm (latimea)
Verificare: 2×19,895+ 2×32,505 = 39,79 + 65,01 = 104,8 cm