Greenland is clearly the larger of the two: about 2,154,754 km² km² against 1,626,369 km² km², roughly 1.3× at true size. Drag one onto the other on the map above to feel the gap.
Greenland sits in North America, Libya 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 1.3×.
The old map muddied it further: Mercator inflates Greenland about 11.8× and Libya about 1.3×, so on a Mercator-style map this pair appears 12.4× apart instead of the true 1.3×.
Libya fits 1× into Greenland.