Réponse :
Longuer fois largeur
Explications étape par étape
ABEF:
Longueur = rac7 + 3 largeur = rac7 + 1
Donc surface = (rac7 +3)(rac7 + 1) = (rac7)² + 3rc7 + rac7 + 3 = 7 + 4rac7 + 3 = 10 + rac7
BCDE: Longueur = rac7 + 1 largeur = rac7 - 2
surf BCDE = (rac7 + 1)(rac7 - 2) = (rac7)² -2rac7 + rac7 - 2 = 7 +rac7 -2 = 5+rac7
ACDE: Long: 2rac7+1 Larg: rac7 + 1
Surf = (2rac7 + 1)(rac7 + 1) = 2(rac7)² + 2rac7 + rac7 + 1 = 2x7 + 3rac7 +1 = 15+3rac7
