MathDB

Geometry Lots of Tangents and Chords

Source:

April 25, 2011

geometry

Problem Statement

Points

C,E,D

and

F

lie on a circle with centre

O

. Two chords

CD

and

EF

intersect at a point

N

. The tangents at

C

and

D

intersect at

A

, and the tangents at

E

and

F

intersect at

B

. Prove that

ON\perp AB

.

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