Răspuns:
perimetrul=2•(lungime+latime)
36=2•(longtime+5)
36=2•5+2•lungime
36=10+2•lungime
scadem 10
26=2•lungime
impartim la 2
lungime=13
P=L x 2 + l x 2
P=L x 2 + 5cm x 2
P=L x 2 + l2
P=L x 2 + 10cm
P=36cm
L2=36cm - l2
L2=36cm -10cm
L2=26cm
L=26cm : 2
L=13cm
