A $12\mathrm{.}5$ m deep cutting is to be excavated in a saturated clay of unit weight $18$ kN$/$m$?.$ The design shear strength parameters are Cu$=37$ kN$/$m$$ and u $=0.$ A hard stratum underlies the clay at a depth of $25\mathrm{.}0$ mbelow ground level. Using Taylor's stability charts,$($a$)$ Determine the siope angle at which failure would occur $($in degrees$).(6)$ What is the allowable slope angle if a factor of safety of $1\mathrm{.}1$ is specified $($in degrees$)?$