Concentric circles problem?

Question

O is the center of 2 concentric circles. Line segment RS is tangent to the smaller circle. If RX = 5 and RS = 30, how can XY be found?

Here is a diagram of the circles:
http://tinypic.com/view.php?pic=4mrfnfs

Answer 1

Label the point where the tangent line touches the circle as Z. Then draw a line from O to Z. Then the triangle OZR is a right triangle. ZR is half SR. So ZR = 15. XO = OZ. The hypotenuse of this triangle is XO + RX = OZ + 5
Use the Pythagorean theorem to get
15^2 + OZ^2 = (OZ+5)^2

Solve for OZ to get your answer.

Answer 2

Quite Easy

OR = 30

=> RX + XO = 30

=> 5 + XO = 30

=> XO = 30 - 5 = 25 units

XY = 2 (XO) = 2(25)

= 50 units.