Drag the dots to make the alternate angles equal.

What happens to the two lines (not the transversal)?

Two sets of Alternate Angles are shown on both diagrams below. One set is shown in blue and the other set
is shown in red.

DIAGRAM 1

DIAGRAM 2

In diagram 2, the lines are parallel.
What do you notice about alternate angles 
on parallel lines?

A = (-5.029863945578234, 1.8281269841269805)
B = (4.342834467120182, 1.0159727891156427)
f = Segment(A, B)
C = (-5.007913832199549, -2.166793650793654)
D = (4.474535147392292, -0.8717369614512503)
g = Segment(C, D)
E = (-2.132448979591838, 2.5744308390022637)
F = (4.474535147392292, -4.010603174603177)
h = Segment(E, F)
G = Intersect(f, h)
H = Intersect(g, h)
α = Angle(A, G, H)
β = Angle(D, H, G)
γ = Angle(H, G, B)
δ = Angle(G, H, C)
I = (16.81049886621316, 1.893977324263035)
J = (24.97594104308391, 1.4769251700680235)
i = Segment(I, J)
K = (16.108095238095245, -1.5960907029478488)
j = Line(K, i)
L = Point(j)
k = Segment(K, L)
M = (20.73956916099774, 2.1793287981859373)
N = (17.53485260770976, -3.0886984126984154)
l = Segment(M, N)
O = Intersect(l, i)
P = Intersect(l, k)
ε = Angle(I, O, P)
ζ = Angle(O, P, K)
η = Angle(P, O, J)
θ = Angle(L, P, O)