Class tutorial

$4\mathrm{.}81$ The following figure gives details of an embankment made of cohesive soil with $=0$ and $c=20k\frac{N}{m^2}.$ The unit weight of the soil is $19k\frac{N}{m^3}\frac{?}{?}$ The weight of the sliding sector is $346$ kN acting at a eccentricity of $5$ m from the centre of rotation. For the trial circle shown, determine the factor of safety against sliding. What would the factor of safety be if the shaded portion of the embankment was removed? In both cases assume that no tension cracks develops.