Thales
Author: HK

A = (3.26, -3.66)
B = (12.3, -3.72)
a = Segment(A, B)
E = Midpoint(A, B)
c = Semicircle(A, B)
C = Point(c)
b = Segment(C, A)
d = Segment(C, B)
α = Angle(A, C, B)
text1: "γ = " + α + ""