A longwall panel is to be developed in a flat seam at a depth of H m. The surface subsidence profile (s) of the area with the horizontal distance x is estimated as
s = S_max/2 [1.002-tanh(4.8x/H)]
where, S_max is the maximum subsidence at the centre of the panel, x is measured from the inflection point. The value of x is negative towards the panel centre and positive towards the panel boundary.
The ratio between the critical width of the panel and the depth is ______ (rounded off to 2 decimal places)