So hmm notice the picture below
I've included the "far arc - near arc" equation to get the angle made by both tangents
now, if we make k = x, which is your case
and we make the "near arc" to "x", which is also the case
and then we make the "far arc" to say "b"
so using the "far arc - near arc" equation, we get that
I've included the "far arc - near arc" equation to get the angle made by both tangents
now, if we make k = x, which is your case
and we make the "near arc" to "x", which is also the case
and then we make the "far arc" to say "b"
so using the "far arc - near arc" equation, we get that