\text{Gegenkathete}\
\text{von }\alpha

\text{Ankathete von }\alpha

\text{Hypotenuse}\
\text{des Dreiecks}

\alpha

\cdot

\beta

\text{Ankathete von }\beta

\text{Gegenkathete}\
\text{von }\beta

A = (6, 1)
B = (9, 1)
C = (9, 3)
d1, c, a, b = Polygon(A, B, C)
α = Angle(B, A, C)
γ = Angle(C, B, A)
β = Angle(A, C, B)