Right circular cone with elliptical section

A right circular cone having apex angle $\alpha=69^\circ$ is thoroughly cut by an inclined plane to generate an elliptical section (as shown by the dotted closed curve in the figure below) . If the angle between axis of cone & the plane is $\theta=73^\circ$ then find out the acute angle ( $<\theta$ in degree) between the plane & the line joining the center of ellipse to the apex of cone.