MathDB

Two perpendicular chords of a circle,

AM, BN

, which intersect at point

K

, define on the circle four arcs with pairwise different length, with

AB

being the smallest of them. We draw the chords

AD, BC

with

AD // BC

and

C, D

different from

N, M

. If

L

is the intersection point of

DN, M C

and

T

the intersection point of

DC, KL,

prove that

\angle KTC = \angle KNL

Problem Statement