a_1 = 3.4 (slider from -5 to 5, step 0.1)
A: (a_1, 0.0)
C = (2.02, 4.18)
b_1 = Line(A, C)
B = Rotate(A, 90.0°, C)
α = Angle(A, C, B)
c_1 = Line(C, B)
c = Segment(A, B)
a = Segment(C, B)
b = Segment(C, A)