Interference of 2 spherical waves

[mariamiguel1921]

Homework Statement

I have these image and I have difficulties in solving two questions.
The first asks to write the curvature of the spherical waves, C1 and C2 after reflecting in the plane and spherical front respectively, as a function of R, radius of curvature of the lens, n index of refraction of the lens and t, the thickness of the lens.
And the second , which asks what the interference pattern is like if the two wavefronts with curvatures C1 and C2 interfere at
a distance −d from the flat face of the lens.

Relevant Equations

none

I believe that to find the curvature C2 is through the ABCD matrices and that C1 has only one phase inversion compared to C. In addition, that the pattern formed is like Newton's rings but I don't know how to find the sizes of the newton's rings depending on lens parameters

 

[haruspex]

The way C is drawn, with that blue arrow angled up from the horizontal, it appears to be from a point source some distance to the left. If that point is $x_1$ from the planar surface and the centre of C1 is $x_2$ from the planar surface then I would have thought C1's radius of curvature was $x_1+x_2$. But $x_2$ is not given.
Likewise, the position of the centre of C2 is not given.