Vendredi 9 avril 2021:
➢ Correction des exercices 56, 57 et 58 p 260 Correction exercice 56 p 260 :
Pa = AB + BC + CA
Pa = 5,5 cm + 3,8 cm + 4,5 cm Pa = 13,8 cm
Donc Pa > Pb
Pb = (13 mm × 4) + (21 mm × 4) = Pb = 52 mm + 84 mm
Pb = 136 mm Pb = 13,6 cm
Correction exercice 57 p 260 : Pa = (8,1 cm × 2) + 7,5 cm Pa = 16,2 cm + 7,5 cm Pa = 23,7 cm
Donc Pa < Pb
Pb = 7 cm + (2,4 cm × 3) + (3,8 cm × 2) + 5,4 cm Pb = 12,4 cm +7,2 cm +7,6
Pb = 27,2 cm
Correction exercice 58 p 260 : Pa = c × 4
Pa = 2,5 cm × 4 Pa = 10 cm
Donc Pa < Pb
Pb = c × 3 Pb = 3,5 × 3 Pb = 10,5cm