MathDB

5 points on a circle, concurrent or parallel wanted - Austrian-Polish 1998

Source:

May 19, 2019

geometryparallelconcurrencyconcurrentcircle

Problem Statement

Different points

A,B,C,D,E,F

lie on circle

k

in this order. The tangents to

k

in the points

A

and

D

and the lines

BF

and

CE

have a common point

P

. Prove that the lines

AD,BC

and

EF

also have a common point or are parallel.