bobby,
It's as well to memorise that a 3° glide slope is about 1 in 20.
A 3.54° glide slope is about 1 in 16.
The way to calculate this yourself is to put your cheap calculator in "degrees" mode, type in "3.54", then press the "tan" key, then the "1/x" key.
Or you can do it without a calculator as follows. You can remember, as above, that 3° is 1 in 20, note that 3.54° is 18% higher (54/3 = 18), and take 18% - let's say 20% - away from 20 to get 16, for your 1 in 16.
This simple arithmetic is not mathematically-bomb-proof accurate, but it's good enough for aviation. You can use it for glide slopes, but after about 8-10° you'd need to start putting in second-order corrections.
PBL