Argentina dwarfs China: about 2,782,703 km² km² against 9,371,225 km² km². At true size Argentina is about 3.4× larger — the whole of China fits into Argentina roughly 3 times.
Argentina sits in South America, China in Asia. On the old Mercator map the latitude gap distorted how large each felt beside the other; at true size the answer is simply 3.4×.
The old Mercator map treated both about equally (1.5× vs 1.6× inflation), so at least their relative sizes were preserved — even if both were drawn at the wrong absolute scale.
Argentina fits 3× into China.