Réponse :
Bonsoir,
Explications étape par étape
AB/15 = 7/3
AB * 3 = 7 * 15
AB * 3 = 105
AB = 105/3
AB = 35
CD/3 = 7
CD = 7 * 3
CD = 21
8/GH = 2/5
GH * 2 = 8 * 5
GH * 2 = 40
GH = 40/2
GH = 20
IJ/4.2 = 4.2/3.6
IJ * 3.6 = 4.2 * 4.2
IJ * 3.6 = 17.64
IJ = 17.64/3.6
IJ = 4.9