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B,D,E,C concyclic, circumcircle and perpendicular related

Source: Singapore Open Math Olympiad 2000 2nd Round p1 SMO

April 2, 2020

geometrycircumcircleperpendicularConcyclic

Problem Statement

Triangle

ABC

is inscribed in a circle with center

O

. Let

D

and

E

be points on the respective sides

AB

and

AC

so that

DE

is perpendicular to

AO

. Show that the four points

B,D,E

and

C

lie on a circle.