a)d'apres pythagore:
BC^2=AC^2+AB^2
=300^2+400^2
=90000+160000
BC=500m
b)AE=BE+AB
=2AB+AB
=3AB
=400×3
=1200m
c)d'apres thalès
AC/AD=AB/AE
300/AD=400/1200
AD=(1200×300)/400
AD=900m
d) d'apres pythagore
DE^2=AD^2+AE^2
=900^2+1200^2
=2250000
DE=1500m
AD=AC+CD
CD=AD-AC
CD=900-300
CD=600m
e) 400+500+600+1500=3000m