10,000ft long : 3048m
2% slope : 200ft drop : 60.96m
150ft wide : 45.72m
volume of triangular wedge under runway = length*'drop'*1/2 * width
I used 3000m * 60m * 50m * 0.5 to give 4.5million
If you use the 'exact' numbers its more like 4.2million
There's also a small inaccuracy in that the 10,000ft is along the runway surface, not horizontal, but that is only another 1 or 2 % error.
edit: I believe you must have used a 2 degree slope, which is equivalent to a 3.5% slope and would, indded, result in approx 7.3million cubic metres of infill
Last edited by Mad (Flt) Scientist; 12th November 2003 at 01:47.