A laser beam enters a circular glass window, forming a chord 15 cm long. If the beam's closest distance to the center of the window is 9 cm, find the radius of the window.

Consider the points A(0, 2), B(2, 3), C(4, 5) and D(0, k). If a circle is drawn through A, B and D where k = 17, then what is the diameter of the circle?

Consider the points A(0, 2), B(2, 3), C(4, 5) and D(0, k). If these points lie on a circle, then what are the possible values of k?