Structure 1 (5 m x 5 m) has a bearing pressure of 36.5 kN/m2, and structure 2 (10 m x 10 m) has a bearing pressure of 80 kN/m2. Determine the MAGNITUDES of the effective vertical (z) and the shear stress in the x-z plane at point A, 7 meters directly below structure 1. Solve for each term of the effective stress equation separately and clearly, and then combine for your final answer. Use L = 30 m.