In the figure above, $$\overline{AB}$$, which has length z cm, is tangent to the circle at point A , and $$\overline{BD}$$, which has length y cm, intersects the circle at point C. If BC = x cm and $$z = \sqrt{xy}$$, what is the value of x?
(1) CD = x cm
(2) $$z = 5\sqrt{2}$$