Greenland is clearly the larger of the two: about 2,154,754 km² km² against 1,296,279 km² km², roughly 1.7× at true size. Drag one onto the other on the map above to feel the gap.
Greenland sits in North America, Peru in South America. On the old Mercator map the latitude gap distorted how large each felt beside the other; at true size the answer is simply 1.7×.
The old map muddied it further: Mercator inflates Greenland about 11.8× and Peru about 1×, so on a Mercator-style map this pair appears 19.1× apart instead of the true 1.7×.
Peru fits 1× into Greenland.