BC = a
AC = b= 12√3
AB =c
A= 30°
B=60°
C=90°
Using the sine rule
[tex]\frac{\sin\text{ A}}{a}=\frac{\sin B}{b}[/tex]
substitute the values into the above
[tex]\frac{\sin30}{a}=\frac{\sin 60}{12\sqrt[]{3}}[/tex][tex]\frac{\frac{1}{2}}{a}=\frac{\frac{\sqrt[]{3}}{2}}{12\sqrt[]{3}}[/tex][tex]\frac{1}{2\times a}=\frac{\sqrt[]{3}}{2\times12\sqrt[]{3}}[/tex][tex]\frac{1}{2a}=\frac{\sqrt[]{3}}{24\sqrt[]{3}}[/tex][tex]\frac{1}{2a}=\frac{1}{24}[/tex]
cross multiply
[tex]2a=\text{ 24}[/tex][tex]a=12[/tex]
Therefore BC = 12
Let's proceed to find AB
[tex]\frac{\sin A}{a}=\frac{\sin C}{c}[/tex][tex]\frac{\sin30}{12}=\frac{\sin 90}{c}[/tex][tex]\frac{\frac{1}{2}}{12}=\frac{1}{c}[/tex][tex]\frac{1}{2\times12}=\frac{1}{c}[/tex][tex]\frac{1}{24}=\frac{1}{c}[/tex]
cross-multiply
[tex]c=24[/tex]
