Bonjour,
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a) p1 = 810 kg/m3 = 810 000 g/m3 = 810 000 000 mg/ m3
b) p2 = 1.925 kg/L = 1925 g/L = 1 925 000 mg/dm3
c) p3 = 0.773 g/cm= 0,000773 kg/cm = 0.773 kg/dm3
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En espérant avoir aidée :)