A thin square plate of one meter by one meter is subjected to a state of plane stress represented by uniform normal stresses ox and ay as illustrated below. All other stresses are zero. The two stresses shown cause the plate to elongate by 0.3 mm in the x direction and by 0.2 mm in the y direction. If it is known that ay is equal to 150 MPa and E is equal to 100 GPa and that all deformations are in the linear-elastic range, determine: a) ox b) the Poisson's ratio for the material from which the square is made, and c) the strain in the thickness direction (z-direction)