Three point-like charges are placed at the corners of a rectangle as shown in the figure. The center of the rectangle. Let q1 = 41 ̂̂̂C, q2 = 1304 ̂̂̂C, and q3 = 3.90 ̂̂̂C. The dimensions of the rectangle are a = 18.0 cm and b = 58.0 cm. Find the electric potential at the center of the rectangle.