2001 Pascal Problem 19

Two circles with equal radii are enclosed by a rectangle, as shown. The distance between their centres is \frac{2x}{3}. The value of x is

\textbf{(A)}\ \frac{15}{4}\quad \textbf{(B)}\ 5\quad \textbf{(C)}\ 6\quad \textbf{(D)}\ \frac{60}{7}\quad \textbf{(E)}\ \frac{15}{2}

If there are no answer choices shown, enter a numerical answer.

Full credit to this problem is given to the CEMC, you may view all Pascal contests here.