I think I saw 300 square km earlier.
Yesterday 1000 square Km was reported, now 3000 which as corrected is 741,000 acres, NOT 74K. We English speakers sometimes have trouble with our metrics. Three thousand kilometers is roughly a square 35 miles by 35 miles. For very rough calculating there are about 3 square kms in a square mile.
If the city to the south of Khirkiv that was taken is in fact a major Russina supply depot, that is very good news, especially if it was captured more or less intact. Hopefully, this new danger will draw more Russians away from the Kherson offensive, at least to the extent they can move, given destruction of bridges, and Uke offensive moves.