3.1 square kilometers is about 766 (766.026683)acres.
Greater London covers an area of 1,579 sq. km (390,179 acres) The City of London covers about 26 sq. km (6,424 acres)
1 (sq kilometer) = 247.105381 acres
80.937 sq km
The state of Virginia encompasses about 27,375,488 acres.
89.03 sq km
16,753,745 acres per 67,800 square km
31 million sq ft = 711.6621 acres (to 4 dp)
The CIA factbook lists Australia at 7,617,930 sq km of land [1] Converting to acres: 7,617,930 sq km = 1.8824315 × 10^9 acres [2] 1.88 billion acres of land [1] https://www.cia.gov/library/publications/the-world-factbook/geos/as.html#Geo [2] http://www.google.com/search?&q=7,617,930+sq+km+in+acres
1 million acres = 4046.856 sq km (to 3 dp).
12,000 acres = 48.56 km2
1 sq km = 100 hectares. 1 sq mile = 2.59 sq km so 509 hectares = 5.09 sq km = 1.97 sq mile. You might also like to remember that 1 sq mile = 640 acres, and 1 hectare = 2.47 acres
Your question is nonsense as:miles are a unit of length; whereasacres are a unit of area.However, if you mean how many SQUARE miles are in 31/2 acres:1 acre = 1/640 sq mi→ 31/2 acres = 31/2 x 1/640 sq mi= 7/1280 sq mi≈ 0.0055 sq mi