→

Zahl_a = 1 (slider from 0.1 to 4, step 0.1)
A = (-4.04, 2.606666666666667)
a_1: abs(Zahl_a)
B = Point(Circle[A, abs(Zahl_a)])
a_3 = Segment(A, B)
b_2 = OrthogonalLine(B, a_3)
c_2 = Circle(B, (4 * Zahl_a))
C = Intersect(c_2, b_2, 2)
d_2 = OrthogonalLine(C, b_2)
e = OrthogonalLine(A, a_3)
D = Intersect(d_2, e)
Vieleck1, a, b, c, d = Polygon(A, B, C, D)
f = Circle(B, Zahl_a)
B_1 = Intersect(f, b, 1)
g = Circle(B_1, B)
F = Intersect(g, b, 2)
h = Circle(F, B_1)
G = Intersect(h, b, 2)
k = Circle(G, F)
umfangVieleck1 = Perimeter(Vieleck1)
PunktVieleck1 = PointIn(Vieleck1)
TextVieleck1: "Umriss von  " + (Name[A]) + "" + (Name[B]) + "" + (Name[C]) + "" + (Name[D]) + " = " + umfangVieleck1 + " "
Text1: "a = " + a + ""
E = PointIn(Vieleck1)