Răspuns :
P=680 cm
L=3 x l ;L=? ;l=?
P=(L+l)x 2
(3l + l)x 2=680
4l x 2=680
4l=680:2
4l=340
l=340:4
l=85
L=85 x 3
L=255
L=3 x l ;L=? ;l=?
P=(L+l)x 2
(3l + l)x 2=680
4l x 2=680
4l=680:2
4l=340
l=340:4
l=85
L=85 x 3
L=255