Răspuns :
Perimetru =2l+2L
L=3l
2l+2*3l=64
8l=64
l=64/8
l=8
L=8*3=24
Verificare
24+24+8+8=48+16=64
L=3l
2l+2*3l=64
8l=64
l=64/8
l=8
L=8*3=24
Verificare
24+24+8+8=48+16=64