8. In the diagram below, the line ST is tangent to the smaller of two concentric circles, and is 36 cm long. Find the area of the annulus (shaded region):
(A) 324 π                   (B) 81 π                   (C) 1296 π                  (D) 162 π
(E) Cannot be determined from given information

9. The figure in the diagram is formed by two overlapping circles. The circles have radii 1 and 3 respectively. If the area of the shaded region is $\frac{\pi }{2}$, then the total area of the figure is

(A) 10 π                (B) $\frac{19\mathrm{\pi }}{2}$                 (C) 8 π           (D) $\frac{7\mathrm{\pi }}{2}$             (E) 9 π