For those of us who don't remember.
Opposite/Hypotenuse
--------------------------- = Opposite/Adjacent
Adjacent/Hypotenuse
Opposite/Adjacent = Tangent
One of the few identities I remember from geometry. Seen it elsewhere, too, been waiting for a while for any excuse, tangential or not, to use it.
I feel better now.
Now, on to my next "lying-in-wait-for-an-excuse-to-use" joke.