Question 691924
If you draw out a triangle, you'll see that AC is opposite the 30 degree angle.



So AC is the shortest leg.



The hypotenuse is twice the shortest leg, so the hypotenuse is 6*sqrt(3) units long. 


So AB = 6*sqrt(3)


The longer leg is sqrt(3) times the shortest leg, so the longer leg is 9 units long. This is because 3*sqrt(3) times sqrt(3) = 3*srt(3*3) = 3*sqrt(9) = 3*3 = 9


So BC = 9