Question 9$ABC$ is right at $A$, altitude $AH = 1 \,\mathrm{cm}$, and angle $B = 60 ^{\circ}$. Find $BC$.$\frac{2}{\sqrt{3}}$$2 \sqrt{2}$$2 \sqrt{3}$$\frac{4}{\sqrt{3}}$$2 \frac{\sqrt{2}}{\sqrt{3}}$