MathDB

Let

\Omega

be a circle, and let

A

B

C

D

and

K

be distinct points on it, in that order, and such that lines

BC

and

AD

are parallel. Let

A'\neq A

be a point on line

AK

such that

BA=BA'

. Similarly, let

C'\neq C

be a point on line

CK

such that

DC=DC'

. Prove that segments

AC

and

A'C'

have the same length.

Problem Statement