Gin,
wrt your second question, I think that you are correct (ish)
500/450 x 760 is actually 844.4 not the figure you quoted.
It is possible that your quoted (correct) answer is wrong.
It happens all the time with feedback from the ATPL exams.
wrt the glideslope problem, tan for small angles almost = sine
I'm note sure that tan is any easier, but just use whichever one you prefer.
But for any obstacle clearance questions it is worth noting that for small climb gradients, the height gained is approximately equal to the ground distance to the obstacle multiplied by the % gradient as a decimal fraction.
So for example, over a 1000m range to an obstacle in a 12% climb ragient you gain about 1000 x 0.12 = 120 m of height.
(or about 393.6 ft)
Last edited by Keith.Williams.; 4th August 2002 at 23:53.