Thinking: this question is about length, width and square, and it should be said that it is a rectangular area.

The units of length and width are meters, so there is no need to unify the units, just multiply them directly. Calculation formula:

140x4

=560 square meters

Length140m, width 4m, 560m2.

1 square is 1 square meter, which is commonly known as 1 square meter.