The figure below shows a light ray coming it parallel to the base of a refracting medium that is in the shape of a quarter circle. The incident light comes from a medium with index of refraction n1 = 1.2, the quarter-circle medium has index of refraction n2 = 1.5 and the medium to the right of the quarter circle has index of refraction n3 = 1.8.

If the incident light ray is a distance H = 20 cm above the base of the quarter-circle medium (which has radius R = 30 cm), determine the distance (x) between the points A and B in the figure.