Răspuns :
P=2x(L+l)
L+l=1480:2
L+l=740
l=L-640
L=l+640
l+640+l=740
2l=740-640
l=100:2
l=50
L=50+640
L=690
Verificare
1480=2x(690+50)
1480=2x740
1480=1480
L+l=1480:2
L+l=740
l=L-640
L=l+640
l+640+l=740
2l=740-640
l=100:2
l=50
L=50+640
L=690
Verificare
1480=2x(690+50)
1480=2x740
1480=1480