North America dwarfs Zambia: about 24,710,000 km² km² against 755,593 km² km². At true size North America is about 32.7× larger — the whole of Zambia fits into North America roughly 32 times.
The old Mercator map treated both about equally (1× vs 1.1× inflation), so at least their relative sizes were preserved — even if both were drawn at the wrong absolute scale.
Zambia fits 32× into North America.