Réponse :
bonjour
980 = 2² x 5 x 7 ²
882 = 2 x 3 ² x 7²
980/882 = 10/9
A = ( 1 /3 - 10/9) x 9 /7
A = ( 3/9 - 10 /9 ) x 9 /7
A = - 7/9 x 9 /7
A = - 63 / 63 = - 1
FP/FB = FO/FS = OP/BS
FB = 120 + 1.5 = 121.5
1.5/121.5 = 1.6/BS
BS = 129.6 m
Explications étape par étape