A glass rod with a refractive index of 1.55 is ground and polished at both ends to hemispherical surfaces with radii of 6.00 cm. When an object is placed on the axis of the rod, 25. cm to the left of the left-hand end, the final image is formed 65.0 cm to the right of the right hand end. What is the length of the rod measured between the vertices of the two hemispherical surfaces?