Răspuns :
AB+BC+CD+DA=54
AB=CD
BC=DA
AB=2BC
AB+BC+CD+DA=54=>2BC+BC+2BC+BC=54=>6BC=54=>BC=9
AB=2BC=2*9=18
AB=CD
BC=DA
AB=2BC
AB+BC+CD+DA=54=>2BC+BC+2BC+BC=54=>6BC=54=>BC=9
AB=2BC=2*9=18
P =2L+2 l
L = 2 l
54 =2 *2 l+2l
6 l =54
l =9 cm
L =2 l =2*9 =18 cm
AB =18 cm
L = 2 l
54 =2 *2 l+2l
6 l =54
l =9 cm
L =2 l =2*9 =18 cm
AB =18 cm