Closer than most people guess: Greenland (2,154,754 km² km²) is only about 16%% larger than Sudan (1,863,027 km² km²).
Greenland sits in North America, Sudan in Africa. On the old Mercator map the latitude gap distorted how large each felt beside the other; at true size the answer is simply 1.2×.
The old map muddied it further: Mercator inflates Greenland about 11.8× and Sudan about 1.1×, so on a Mercator-style map this pair appears 12.6× apart instead of the true 1.2×.
Sudan fits 1× into Greenland.