Gegenkathete

Gegenkathete

In a right triangle, T, with a hypotenuse c, and katheten of a and b, with verticies meeting at angles α, β, and γ (where γ is π radians (90 degrees (no one really cares about degrees))),

            α
             |\
             | \
             |  \ 
          b  |   \ c
             |    \
             |     \
             |______\
            γ        β  
                 a

          Gegenkathete    a
sin(α) =  ------------ = ---
           Hypotenuse     c

          Gegenkathete    a
tan(α) =  ------------ = ---
            Ankathete     b

It is used almost exclusively in German trigonometry, and I assume it means "Opposite Leg", although like the word "hypotenuse", it has Greek origins. Strangely, kathete has been dropped from the majority of western trigonometry.