grootte hoek α

A = (0, 0)
B = (20, 0)
p = 25 (slider from 0 to 90, step 0.1)
C, D = Intersect(d, xAxis)
E = Rotate(D, p 3.141592653589793 / 180, B)
α = Angle(D, B, E)
a = Segment(B, E)
F, G = Intersect(c, xAxis)
H = Rotate(F, -p 3.141592653589793 / 180, A)
β = Angle(H, A, F)
b = Segment(A, H)
e = Segment(A, B)
poly1, h, a_1, b_1, e_1 = Polygon(H, A, B, E)