tg α =  \frac{ 2 }{3 } 

E = (-9.887932695914548, 0.7285634914038998)
F = (43.079848093802575, 1.1530603988905017)
c = Line(E, F)
O = (-4.888302452183457, -3.37490661429992)
B_1 = (15.487549107173415, -3.3749066142999196)
a_1 = Ray(O, B_1)
b = OrthogonalLine(O, a_1)
C = Point(b)
d = Ray(O, C)
D = (-11.019924449212153, -10.025358164923352)
G = (-6.491957436021732, -10.119690811031486)
a = Segment(D, G)
e = Circle(O, a * 2.0)
A = Intersect(e, a_1, 1.0)
f = Circle(O, a * 3.0)
B = Intersect(f, d, 1.0)
g = Segment(B, A)
α_1 = Angle(A, O, B)
α = Angle(O, B, A)
khoangcachOA = Distance(O, A)
Văn bảnOA: "\overline{" + (Name[O]) + (Name[A]) + "} \, = \, " + khoangcachOA
khoangcachBO = Distance(B, O)
Văn bảnBO: "\overline{" + (Name[B]) + (Name[O]) + "} \, = \, " + khoangcachBO