I'm asking this question because Wikipedia shows a table with slope, gradient and grade calculated by tangentandby 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 istheone 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 functionandby the sine function.

However, what are the applications of asine functionslope or grade calculation? For example is this used by roofers, mountain climbers, cyclists, etc?