Ipotesi:
ABC isoscele ⇒ACB≅ABC, AC≅AB
EC≅BD
AH≅AK

Tesi:
EH≅DK

Dimostrazione
Si ha che ECH≅BDK in quanto
- EC≅BD per ipotesi
- angoli HCE≅ABD supplementari si angoli congruenti
- HC≅KB differenza di segmenti congruenti (ipotesi)

Quindi EH≅DK cvd

C = (0.64, -0.86)
B = (3.12, -0.88)
a = Segment(C, B)
b = LineBisector(C, B)
A = Point(b)
poli1, b_1, a_1, c = Polygon(C, A, B)
d = Line(C, B)
D = Point(d)
e = Segment(B, D)
f = Circle(C, e)
E, F = Intersect(f, d)
g = Segment(E, C)
G = (3.92, 1.6)
h = Circle(A, G)
H = Intersect(h, b_1)
K = Intersect(h, a_1)
i = Segment(A, H)
j = Segment(A, K)
k = Segment(E, H)
l = Segment(D, K)
α = Angle(A, B, C)
β = Angle(B, C, A)