Répondre :
Aire(T1)=AExAD/2=800x/2=400x
Aire(T3)=BCxBE/2=500(700-x)/2=250(700-x)=175000-250x
Aire(Totale)=(BC+AD)xAB/2=(500+800)x700/2=455000
Aire(T2)=Aire(T1)+Aire(T3)=(1/2)Aire(Totale)
400x+175000-250x=455000/2
150x=227500-175000
150x=52500
x=52500/150=350m