The Shulbasutras of Baudhayana, Apastamba, Katyayana and Manava: With Text, English Translation and Commentary c7.21

c7.21

If it is desired to transform a rectangle into a square, its breadth is taken as the side of a square (and this square on the breadth is cut off from the rectangle). The remainder (of the rectangle) is divided into two equal parts and placed on two sides (one part on each). The empty space (in the corner) is filled up with a (square) piece. The removal of it (of the square piece from the square thus formed to get the required square) has been stated.