The figure below shows a triangle ABC with the
orthocenter H and the internal bisector BD. Line EHF is perpendicular to
BD. The circumcircle of the triangle BEF cuts the circumcircle of the
triangle ABC at G. Prove that the measure of angle HGB is 90 degrees.

See also

Art of problem 1384

Conformal Mapping or Transformation of Problem
1382

Geometry Problems

Ten problems: 1381-1390

Visual Index

Open Problems

All Problems

Circle

Triangle

Angle Bisector

Orthocenter

Circumcircle

90 Degree

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