CYCLIC QUADRILATERAL

show any four points on circle

An example of cyclic quadrilateral

which is one pair of opposite angles

show another vertex and its opposite angles

radius = 3 (slider from 1 to 25, step 1)
O = (-0.638004159313484, 4.059838552832965)
Circle = Circle(O, radius)
A = Point(Circle)
B = Point(Circle)
C = Point(Circle)
D = Point(Circle)
b = true
f = Segment(D, A)
g = Segment(A, B)
h = Segment(B, C)
i = Segment(D, C)
c = true
α = Angle(B, A, D)
β = Angle(C, B, A)
γ = Angle(D, C, B)
δ = Angle(A, D, C)
Sum: α + γ
text3: "SUM OF OPPOSITE  ANGLES = ∠ A  +  ∠C
                                                       =" + α + " +" + γ + "
                                                        =" + Sum + "
                                                       "
d = true
e = true
sum2: β + δ
text2: "SUM OF ANOTHER PAIR OF OPPOSITE ANGLES  = angle B  +  angle D
                                                                                           =" + β + "  +   " + γ + "
                                                                                           =   " + sum2 + ""