Răspuns :
Diagonalele se taie in jumatati egale, asadar ne putem incadra intr-un triunghi cu unghi drept det de diagonalele perpendiculare. Asadar l^2=diag/2^2+diag cealalta/2^2
l^2=4^2+3^2
l^2=25
l=5
P=4*5=20 cm
l^2=4^2+3^2
l^2=25
l=5
P=4*5=20 cm