use the 30* 60* 90* rule where
30* = x, 60* = x√3, 90* = 2x
so based on the given,
2x = 6√3 ⇒ divide both sides by 2 and you'll end up with
x = 3√3 (the length side of JK)
to find JL, multiply 3√3 by √3 and the answer'll be 9 = length of JL, opp of 60*