
Brent K. answered 07/09/21
Applied Math PhD
Hi Henry,
Someone else could possibly provide further context, but the reason, as I see it, is due to similar triangles - similar triangles have side ratios (i.e. the result of division) that are the same, and it's this fact that even lets us define the trig functions of an angle to begin with


Mark M.
A distinction must be made between right-triangle trigonometry (to which you refer) and trigonomtric functions.07/10/21
Andrew D.
07/09/21