In the construction of an ellipse using concentric circles of radii 4cm and 6cm, a radial line is drawn at an angle θ from the center. A vertical line is drawn from the intersection of the radial line with the outer circle, and a horizontal line is drawn from the intersection with the inner circle. These lines meet at point P. If the area of the rectangle formed by P, its projection on the x -axis, the origin, and its projection on the y -axis is 63cm2, find the possible values of the angle θ (where 0<θ<90∘).