Closer than most people guess: Greenland (2,154,754 km² km²) is only about 15%% larger than Indonesia (1,872,242 km² km²).
Greenland sits in North America, Indonesia 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 1.2×.
The old map muddied it further: Mercator inflates Greenland about 11.8× and Indonesia about 1×, so on a Mercator-style map this pair appears 13.6× apart instead of the true 1.2×.
Indonesia fits 1× into Greenland.