In the figure above, \(\frac{x}{\sin 60^o} = \frac{10}{\sin 30^o}\) (Sine rule)

x = \(\frac{10 \sin 60^o}{\sin 30^o}\)

= 10 x \(\frac{\sqrt{3}}{2} \times \frac{1}{2}\)

= 10 x \(\frac{\sqrt{3}}{2} \times \frac{2}{1}\)

= 10\(\sqrt{3}\)cm