Cyclic Quadrilaterals

If all the vertex of the quadrilateral comes on a circle then it is said to be a cyclic quadrilateral.

Theorem 10: Any pair of opposite angles of a cyclic quadrilateral has the sum of 180º.

\angle A + \angle B + \angle C + \angle D = 360º (angle sum property of a quadrilateral)

\angle A + \angle C = 180°

\angle B + \angle D = 180º

Theorem 11: If the pair of opposite angles of a quadrilateral has sum of 180º, then the quadrilateral will be cyclic.

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