Răspuns :
L = 20 cm
l = 4/5 * L
l = 4/5 *20 = 80 / 5 = 16
l = 16 cm
P = 2L + 2 l
P = 2 * 20 + 2 * 16
P = 40 + 32
P = 72 cm
l = 4/5 * L
l = 4/5 *20 = 80 / 5 = 16
l = 16 cm
P = 2L + 2 l
P = 2 * 20 + 2 * 16
P = 40 + 32
P = 72 cm