Bonjour,
l = x
L = 3x
D= x
Périmètre du cercle : ( 1/2 + 1/2) =1
Formule: 3,14 * D
3,14 *x + 2*3x = 400
3,14x + 6x = 400
9,14x = 400
x= 400/9,14 =>43,76m
l = D = 43,76
P cercle: 3,14 * 43,76 => 137,41cm
L = 43,76 * 3 = 131,28
2*131,28 + = 137, 41 => 399, 97m => 400m