The path itself goes up at a steep angle but it also cuts across an inclined plane. I wondered how the geometry affected the actual slope climbed. I find that the steepest slope for walkers to be OK is about 45 degrees so I've modelled it at a 30 degree slope.First of all I drew a 100m line going up a 30 degree slope across a vertical face. I've said it is 100m above the ground. The height gain from A to B would be 100sin(30) = 50 metres. The slope is said to be 1 in 2 (or 50%) because you go up 1 metre for every 2 metres along the path.
Then I took the diagram and tilted it over to an angle of 30 degrees to mimic the situation on Fisher's Wife's Rake. Now A would be 50 metres above the ground and B would be 75 metres, so by walking 100 metres you would end up 25 metres higher. That's a slope of 1 in 4 or 25%. By angling across a plane, the gradient can be reduced.