Argentina dwarfs South America: about 2,782,703 km² km² against 17,840,000 km² km². At true size Argentina is about 6.4× larger — the whole of South America fits into Argentina roughly 6 times.
The old Mercator map treated both about equally (1.5× vs 1× inflation), so at least their relative sizes were preserved — even if both were drawn at the wrong absolute scale.
Argentina fits 6× into South America.