bonjour
le triangle ADC est rectangle en C
AD² = CA² + CD²
AD² = 3.6 ² + 1.05 ² = 14.0625
AD = √ 14.0625 = 3.75 m
AB = 3.6 + 8.4 = 12 m
AC/AB = AD/AE = CD/BE
3.6 /12 = 3.75 /AE ⇔ AE = 12.5
longueur de la rampe = 12.5 m