Given that the normal and shear stresses on two mutually perpendicular planes $BC$ and $BA$ in a soil element are:

$BAin$ a soil element are:

${}_x=140K\frac{N}{m^2}$;${}_y=60K\frac{N}{m^2}$;${}_{xy}=20K\frac{N}{m^2}$;${}_{yx}=-20K\frac{N}{m^2}$

Determine

a$)$ The major principal stress

b$)$ The minor principal stress

c$)$ The normal and shear stress on plane $CA,$ which makes an angle of $37.$ Use pole Method of Mohr's diagram.