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2006 AMC 12A Question 17

AMC12 · 2006 AMC 12A

Question 17

Square $ABCD$ has side length $s,$ a circle centered at $E$ has radius $r,$ and $r$ and $s$ are both rational. The circle passes through $D,$ and $D$ lies on $\overline{BE}.$ Point $F$ lies on the circle, on the same side of $\overline{BE}$ as $A.$ Segment $AF$ is tangent to the circle, and $AF = \sqrt{9 + 5\sqrt{2}}.$ What is $\frac{r}{s}?$

Question illustration
  1. $\dfrac{1}{2}$
  2. $\dfrac{5}{9}$
  3. $\dfrac{3}{5}$
  4. $\dfrac{5}{3}$
  5. $\dfrac{9}{5}$