The state of stress at a point in a machine element of irregular shape, subjected to com...

The state of stress at a point in a machine element of irregular shape, subjected to combined loading, is given by

A torsion test performed on a specimen made of the same material shows that yielding occurs at a shearing stress of 9 MPa. Assuming the same ratios are maintained between the stress components, predict the values of the normal stresses at which yielding occurs at the point. Use maximum distortion energy theory.