An B_n ziehen/schieben!

A = Intersect(xAxis, yAxis)
B = Point(xAxis)
C = Point(yAxis)
f = Segment(C, B)
g = Segment(A, B)
h = Segment(C, A)
E = Point(xAxis)
F = Point(h)
G = Point(xAxis)
d2, f_1, a_1, g_1 = Polygon(A, G, F)
H = Point(h)
I = Point(xAxis)
d3, h_1, a_2, i = Polygon(A, I, H)
v = Vector(B, E)
d4, c, a_3, b = Polygon(A, B, C)
D = Point(xAxis)
m = Segment(B, D)
B_n = Point(m)
l = Vector(B, B_n)
j = Segment(B, B_n)
d = Circle(C, j)
C_n = Intersect(d, h)
u = Vector(C, C_n)
d1, c_n, a, b_n = Polygon(A, B_n, C_n)
α = Angle(B, A, C)
Text1: "Länge der Strecke  \overline{B_nC_n}: " + (LaTeX[a]) + " cm"