bonjour
calcul de BC
BC² = 300 ² + 100 ²
BC² = 250 000
BC = √250 000 = 500 m
CA/CE = CB/CD = AB/DE
400/1000 = 500 /CB ⇔ CD = 500000/400 = 1 250 m
ED = 500/1250 = 300/ DE ⇔ ED = 375 000 : 500 = 750 m
parcours = AB + BC + CD + DE
= 300 + 500 + 1 250 + 750 = 2 800 m = 2.8 km