(x+2*2)^2=816(x+4)^2=816x+4=28.565713714171399991997599245469x=24.565713714171399991997599245469x^2=603.47429028662880006401920603625原来的面积 603.47429028662880006401920603625
设原来的边长为x米,则(x+2)^2=816,解得:x+2=28.5657,x=26.5657,原来的面积x^2=705.737平方米