Cyclic Quadrilateral Property

To verify that opposite angles of a cyclic quadrilateral are supplementary.

A quadrilateral is a closed shape and a type of polygon that has four sides, four vertices and four angles. It is formed by joining four non-collinear points.

Following are examples of a quadrilateral.

**Fig. (A) Polygon**

A cyclic quadrilateral is a quadrilateral which has all its four vertices lying on a circle. It is also called an inscribed quadrilateral.

**Fig. (B) Cyclic Quadrilateral**

Supplementary angles are those angles that sum up to 180°. For example, angle 120° and angle 60° are supplementary angles because the sum of 120° and 60° is equal to 180°.

**Fig. (C) Supplementary Angles**