To start the animation right click the slider below and activate the animation. 

a = -1.67 (slider from -5 to 5, step 0.01)
b: RandomUniform[0, 1] + (0 * a)
c: RandomUniform[0, 1] + (0 * a)
A_1: (b, c)
B = (1.6771987961072508, 0.9692997133802407)
C = (4.720298800742386, 0.8687609056815273)
A = (2.3605506556459273, 2.8453969989858567)
mnogokotnik1, d, b_1, c_1 = Polygon(B, C, A)
E = Intersect(xAxis, yAxis)
F: B + (b * (C - B)) + (c * (A - B))
e = Ray(A, F)
f = Ray(C, F)
g = Ray(B, F)
G = Intersect(b_1, g)
H = Intersect(c_1, f)
I = Point(e)
p = Circle(H, G, A)
L = Intersect(d, e)
h = Circle(C, G, L)
J = Intersect(p, h, 2)
i = Segment(B, C)
j = Segment(C, A)
k = Segment(A, B)