I *think* it uses 'feet' instead of metres. Please dont use TAN. It reminds me too much of Year 10 maths! :) That bloody SOHCAHTOA thing... AAAARGH! Hubert Lam wrote: > Sorry does "1 in 40" mean tan x = 1/40 (rises 1 metre vertically for every 40 metres of horizontal > track) or does it have some other meaning? -- Anita Lukaszyk neety@ozemail.com.au http://www.ozemail.com.au/~neety