0°

O = (237.62442765836542, 279.3523000757011)
B = (285.07000769079394, 251.93929827918686)
c = Circle(O, B)
C = (315.6460481561368, 279.3523000757011)
a = Line(O, C)
D = Intersect(c, a, 1.0)
E = Intersect(c, a, 2.0)
d = Ray(D, E)
X = Point(d)
e = Segment(D, X)
f = Semicircle(D, E)
A = (400.6966434735273, 277.94650511177736)
G = (478.7182639712987, 278.64940259373924)
g = Segment(A, G)
H = (449.54801846987965, 319.76890528851067)
h = Segment(A, H)
α = Angle(G, A, H)
Y = Rotate(X, α, O)
b = Segment(O, Y)
β = Angle(X, O, Y)