Prove that opposite sides of a quadrilateral circumscribing a circle subtend supplementary angles at the centre of the circle .

Prove that opposite sides of a quadrilateral circumscribing a circle subtend supplementary angles at the center of the circle.

Prove that opposite sides of a quadrilateral circumscribing a circle,subtend supplementary angles at the centre of a circle.

Prove that the opposite sides of a quadrilateral circumscribing a circle subtend supplementary angles at the centres of the circle.

Prove that opposites of a quadrilaterial circumscribing a circle subtend supplementary angles at the centre of the circle.

Equal chords of a circle subtend equal angles at the centre.

Equal chords of a circle subtend equal angles at the centre.

Prove that opposite angles of a cyclic quadrilateral are supplementary

Prove that equal chords of a circle subtend equal angles at the centre.