Question

One side of rectanglur feild of area0.5ha is125m find the other side in m

Answer 1

1 ha (hectare) = 10,000 square meters
we have a rectangle with an area of 5,000 square meters and one side measuring 125 meters.
The "other side" is 5,000 / 125 = 40 meters .
If you mean the opposite side, of course that's 125 m, because the field is rectangular.