A cyclic Quadrilateral is a special type of quadrilateral that can be inscribed inside of a Circle.

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Properties
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Common Cyclic Quadrilaterals
Ptolemy's Theorem
Ptolemy's Theorem states that
theorem can be proved by drawing point
Thison
such that
similarity, we have that
From triangleand
Cross-multiplying and then adding both equations gives us
We know that
, so hence,
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