About 1/2 acre (0.45913682 acres).
About 0.46 acres.
20000m2 is about 4.5 (4.9421076) acres.
80.937 sq km
20,000 sq ft is 0.459 acre.
60113 sq feet = 1.38 acres, approx.
49400 sq feet = 1.13 acres (approx)
435,600 sq feet.
10,454.4 sq feet.
174,240 sq feet.
3 billion sq feet = 68870.5 acres
(20,000 acres) / (640 acres per sq mile) = 31.25square miles