relationships between the coordinates X, Y, of a point, in order to belong in a circular ring part

Question

I like to find a set of mathematical relationships between the coordinates X, Y, of a point, in order to belong in the space between two concentric circles (O, r) and (O, R) and within a circular sector angle d degrees. Lets assume the center on the 0,0 cartesian point , and the 0 degrees is on the write half of the horizontal axis (three o'clock). ---- A shape on this link https://www.dropbox.com/s/sxycyvh6hgk7cps/circular%20ring%20sector%20%20red.png describes the question . in order for a point to be in the red area.

Answer 1

1. r^2 < x^2 +y^2 < R^2... That long bunch av konfuzed werds bout write-horizontal axis & 3 O'klok is hard tu tell... me ges yu thank yu spesifi a angel from the x-axis.... yu fael... go bak tu jael