Angle Bisectors in a Quadrilateral: What is it about?
A Mathematical Droodle
Angle bisectors in a quadrilateral form another quadrilateral which is cyclic, i.e. a quadrilateral that can be inscribed in a circle. Indeed, the sum of opposite angles of the latter is always 180o. The same holds true for the external angle bisectors.
Copyright © 1996-2010 Alexander Bogomolny
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