The radius of the trial slip surface given in the following figure is 18m. The water table is assumed to be at the upper surface of the slide. The saturated unit weight, effective friction angle, and effective cohesion of soil are 24 kN/m3, 140, and 16 kN/m2 , respectively. The trial slip surface to be analysed using "Fellenius Method" . The trial surface was first divided into three slices and for each slice, width (b), height (h), weight (W), pore-water pressure at mid- point of base (u), and the inclination of slice base to the horizontal () are given the following table. Determine the factor of safety of the slope against sliding along the trial surface using Fellenius method