Monday, December 19, 2011

Problem 706: Triangle, Cevian, Circumcenters, Three Circumcircles, Concyclic Points

Geometry Problem
Level: Mathematics Education, High School, Honors Geometry, College.

Click the figure below to see the complete problem 706.

Online Geometry Problem 706: Triangle, Cevian, Three Circumcenters, Circumcircles, Concyclic Points<br />

2 comments:

  1. ∠EBO =∠OBA-∠EBA =(90°-∠BCA)-(90°-∠BDA)
    =∠BDA-∠BCA=∠DBC=∠EFO (since EF⊥DB and OF⊥CB)
    ∴ E,O,F,B are concyclic

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  2. Note that OE and OF are perpendicular bisectors of AB and AC.
    So angle(EOF) supplement to angle(EOF) and E,O,F,B are concyclic

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