At true size, Russia is about 0.9× the size of South America. On the old 1569 Mercator map the same two appear about 5.7× apart — the old map exaggerates their difference by a factor of 6.1×.
It is a latitude illusion: Russia sits near 66°, where Mercator multiplies area by about 6.1×, while South America lies near 10°, inflated only about 1×. Equal Earth removes that latitude tax, and the pair settles at its honest 0.9×.