How many kilometers in one million acres?

Answer 1

NONE!!!!

Because 'kilometres' is a metric measure of length. 'Acres' is an Imperial measure of area.

You cannot directly compare length with area. However, a length multiplied to a perpendicular length will give an area.

Answer 2

The question, as stated, cannot be answered sensibly. An acre is a measure of area, with dimensions [L2]. A kilometre is a measure of distance, with dimensions [L]. The two measure different things and elementary dimensional analysis teaches that you cannot convert between measures with different dimensions such as these without additional information.