Originally Posted by
Keith99
Wrong.
According to the link previously given, they say
Measuring the distance along the surface of the road (c) instead of horizontally (b) gives practically
the same result for most road gradients up to 10%. For instance, a 20% grade (11.3 degrees), measuring
along the road surface gives a 19.6% grade (you must have a tangent handbook or calculator to properly
calculate these figures).