Answer:
an area
Explanation:
A two-dimensional (2D) figure is like drawing on a sheet of paper. It has some width and some length, but no height.
So, you cannot calculate its volume, since it has only 2 dimensions, a volume requires 3 dimensions.
The only spacial measure you can do on a two-dimensional figure is its area (basically length * width, if we talk about a rectangle, other forms have different calculation methods).