AZ=12 - is hypotenuse
∠XZY=30° ⇒
[tex]XY=\dfrac{1}{2} \times12=6[/tex]
[tex]\text{By the Pythagorean theorem}\\YZ=\sqrt{12^2-6^2} =\sqrt{(12-6)(12+6)} =\sqrt{6\times18} =\sqrt{108} =6\sqrt{3}[/tex]
