Definition:Cyclic Quadrilateral

This page is about cyclic quadrilateral. For other uses, see cyclic.

Definition

A cyclic quadrilateral is a quadrilateral which can be circumscribed:

This is an example of a quadrilateral which cannot be circumscribed, and so therefore is not cyclic:

Also see

• Ptolemy's Theorem

• Results about cyclic quadrilaterals can be found here.

Sources

• 1989: Ephraim J. Borowski and Jonathan M. Borwein: Dictionary of Mathematics ... (previous) ... (next): cyclic quadrilateral
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): cyclic
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): cyclic