bonjour
j'en fais 1
AE/AD = AB/AC = EB/CD
AB² = 3²+ 4² = 9 + 16 = 25
AB = √25 = 5 cm
AB/AC = BE/CD
5/AC = 3/7.5 ⇔ AC = 12.5 cm
BC = 12.5 - 5 = 7 .5 cm