If that's supposed to be a square, just do the multiplication. The answer will be in square meters.
144 square meters
1600mm x 1600mm is 2.56 square meters.
18.39 square meters.
9 square meters
36 square metres
40 x 40 = 1,600 square meters.
20 x 10 = 200 square meters.
500 x 315 = 157,500 square meters.
7 x 4 = 28 square meters.
12.54 square meters.
6.04 square meters.
20.07 square meters.