@ktmb
Dude, though I do not see any fault with the trig solution of yours, I cant help but feel that you can apply basic trigonometry to solve this one (why? I dont know).
As for the other two solutions. If you use 6080/3600 (instead of 100/60) in the 1:60 rule method then you will get the same answer for both the 1:60 rule method as well as the unitary method, which is 1230 ft/min.