3.11) In the following stress element, the stresses on the x-face are known 105 MN/m^2 for xx, and 56MN/m^2 for xy, but the normal stress (sigma_(yy)) is unknown. a.) If the minimum principal stress is (-7MN//m^(2)), determine the required (sigma_(yy)) and the maximum principal stress. b.) Draw the corresponding three-dimensional Mohr's circle. c.) Using the (sigma_(yy)) calculated in part (a), verify the principal stresses by the eigenvalue analysis. d.) If this material has a tension yield stress of 180MN//m^(2), calculate the margin of safety using the maximum principal stress. Assume a factor of safety of (1.25)