If diagonals of a cyclic quadrilateral are diameters of the circle through the vertices of the quadrilateral, prove that it is a rectangle.
ABCD is a cyclic quadrilateral whose diagonals intersect at a point E. If , is , find . Further, if AB = BC, find .
In figure, A, B, C and D are four points on a circle. AC and BD intersect at a point E such that and . Find .
In figure, , , find .
In figure, , where P, Q and R are points on a circle with centre O. Find .