Tangent function determines slope, gradient or grade of a road, but what about sine?
I'm asking this question because Wikipedia shows a table with slope, gradient and grade calculated by tangent and by sine.
The article is here:
Grade (slope) - Wikipedia, the free encyclopedia
and the table is just a short scroll down.
I know slope is always defined as rise over the run so the tangent function is the one to use but still, the sine function seems to have its applications.
In the table it says a 45º angle is a 100% grade (by tangent function) but using the sine function it is 70.711%. A 90º angle is a 100% grade when calculated by sine and infinite by the tangent function.
So, I know how to calculate the slope, gradient, grade, etc of a road by the tangent function and by the sine function.
However, what are the applications of a sine function slope or grade calculation? For example is this used by roofers, mountain climbers, cyclists, etc?