This question cannot be answered sensibly. An acre is a measure of area, with dimensions [L2]. A kilometre is a measure of distance, with dimensions [L]. The two measure different things and basic dimensional analysis teaches that you cannot convert between measures with different dimensions such as these without additional information.
However, if you meant square kilometers, then 7,860 acre = 31.80829148 square kilometers.
Answer: 2 km² = 494.210 acres
Seven (7) square km equates to about 1,730(1,729.73767) acres.
Answer: 50 acres = 0.202342 km²
150 acres is 0.607028 km2
20 acres = 0.08093713 km2
Answer: 12,500 acres = 50.5857 km²
Answer: 1 km² = 247.105 acres
1 Square Kilometer = 247.105381 Acres
25 acres is 0.101171 square km
580 acres (2.3 km 2)
1.38 acres is 0.00558 square km
10 acres is 0.0404686 square km