Related circumferences

Hi! im having some trouble with my model. 

Ill attach the Rhino with some references.

I need to have an initial point, from were the first and second circumference raises. The first circumference should be x% less than the second one. the percentage should be variable. 

Both radius should vary with the same parameter, always mantaining the % relationship.

From the center, there should be a polygon which radius is the same as the second circumference, and the amount of vertices should increase when the radius increases, and decrease when the radius decreases. 

The lines should connect the center and the intersections of the polygon. 

Thanks