Tan a = 0.95/0.75 = 1.27
a = Tan-1 1.27 = 51.78deg?

dohddub: since this is your first post it's impossible for us to tell what problem you are trying to work out. Yes, the arctan of 1.27 is indeed 51.78 degrees, but I suspect that your real question has to do with the factors 0.95 and 0.75. Also, you rounded 0.95/0.75 to 1.27, which is 3 significant digits - that's OK but then you shouldn't express the arctan(1.27) to 4 significant digits. If you actually calculated arctan(0.95/0.75) you would see it equals 51.71 degrees.