Geotechnical Engineering: Slope Stability - Finite Slope

A cut slope was excavated in saturated clay as shown below. The slope made an angle of 60deg. Along horizontal. When slope failure occurs. Distance BC is 8m . Stability Number, m = 0.185 unit weight= 17.5 kN/m^3 cu = 22 kPa.
a. Stability Factor
b. Critical Depth
c. Angle of Failure Plane