Since you don't have any angle and its opposite side, you cannot establish the ratio for the law of sines, so you must use the law of cosines.
[tex] c^2 = a^2 + b^2 - 2ac \cos C [/tex]
Let's change it for this problem.
[tex] r^2 = p^2 + q^2 - 2pq \cos R [/tex]
[tex] r^2 = 9^2 + 6^2 - 2(9)(6) \cos 34^\circ [/tex]
[tex] r^2 = 9^2 + 6^2 - 2(9)(6) \cos 34^\circ [/tex]
[tex] r^2 = 27.46 [/tex]
[tex] r = 5.24 [/tex]
[tex] PQ = 5.2~km [/tex]
