Răspuns :
P = 2 ( L + l )
L = 4 l
( P = 90 ) => 90 = 2 ( 4 l + l )
90 = 2 · 5 l
90 = 10 l / :10
l = 9 m
L = 4 l
L = 4 · 9
L = 36 m
L = 4 l
( P = 90 ) => 90 = 2 ( 4 l + l )
90 = 2 · 5 l
90 = 10 l / :10
l = 9 m
L = 4 l
L = 4 · 9
L = 36 m