1999 AIME Problem 6

A transformation of the first quadrant of the coordinate plane maps each point (x,y) to the point (\sqrt{x},\sqrt{y}). The vertices of quadrilateral ABCD are A=(900,300), B=(1800,600), C=(600,1800), and D=(300,900). Let k_{} be the area of the region enclosed by the image of quadrilateral ABCD. Find the greatest integer that does not exceed k_{}.

Leading zeroes must be inputted, so if your answer is 34, then input 034

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.