What has an area of 1 km2?

Answer 1

Anything two dimensional whose dimensions equate to an area of 1 Km2.

It depends on the shape of the specific object in question as to how we calculate area, but to keep things simple let's look at a rectangle. A rectangle's area is simply its length multiplied by its width. So:

For example a perfectly flat rectangular field with dimensions 1 Km by 1 Km would have an area (surface area) of 1 Km2. (1 * 1 = 1)

Equally, if the dimensions of the field were 0.5 Km by 2 Km then the area would also be 1 Km2. (0.5 * 2 = 1)