The area of the first square is (40/4) square, that is, 100 square centimeter, and the area of the second square is half that of the first square, that is, 1/2, so the area of the sixth square is

100 *1/2 *1/2 *1/2 *1/2 = 3.125 (square centimeter)

1 second, third, fourth, fifth and sixth