Răspuns :
[tex]l=3cm[/tex]
[tex]L=3*4=12cm[/tex]
[tex] P_{d} =2*(L+l)[/tex]
[tex] P_{d} =2*(3+12)=2*15=30cm.[/tex]
[tex]L=3*4=12cm[/tex]
[tex] P_{d} =2*(L+l)[/tex]
[tex] P_{d} =2*(3+12)=2*15=30cm.[/tex]