[填空题]
$\text { The following diagram shows triangle } \mathrm{ABC} \text {, with } \mathrm{AB}=9 \mathrm{~cm}, \mathrm{BC}=6 \mathrm{~cm} \text {, and } \mathrm{ABC}=\frac{\pi}{3} \text {. }$
1. Show that $\mathrm{AC}=3 \sqrt{7} \mathrm{~cm}$ .
2. The shape in the following diagram is formed by adding a semicircle with diameter [A C] to the triangle.
