MathDB

Circle !

Source:

February 4, 2015

Problem Statement

Let

AB

and

CD

be chords in a circle of center

O

with

A , B , C , D

distinct , and with the lines

AB

and

CD

meeting at a right angle at point

E

. Let also

M

and

N

be the midpoints of

AC

and

BD

respectively . If

MN \bot OE

, prove that

AD \parallel BC

.

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