Geological mapping question

[Son of Scylla]

I am having trouble figuring out a geology mapping problem. The problem is "Slickensides Oligoshain Formation pitch 60 degrees N on a fault oriented at 335 degrees, 60 W. What is the plunge of the slickensides". I kept getting arctan of 1.5 as my answer, but the answer key disagrees.  Any help would be appreciated.

[DPS Ammonite]

To quote Chevy Chase, "I was told there would be no math." Hopefully a real field geologist can step up and help.

[Scylla]

He's gonna make me re-learn Trigonometry if you guys can't help