If a parallelogram is cyclic, then it is a rectangle. Justify.

Rewrite each of the following statements in the form ''p if and only if q'' r: If a quadrilateral is equiangular, then it is a rectangle and if a quadrilateral is a rectangle, then it is equiangular.

Show that the points (-2,-1),(5,4),((6,7) and (-1,2) are the vertices of a parallelogram .Is the parallelogram a rectangle ?

Prove that if the lengths of the two diagonals of a parallelogram be equal , then the parallelogram is a rectangle.

Prove that if one of the angles of a parallelogram be a right -angle , then it should be a rectangle.

By vector method show that , the parallelogram whose diagonals are equal is a rectangle ,

Using dot product of vectors, prove that a parallelogram, whose diagonals are equal, is a rectangle

Cyclic AMP is

Prove that a cyclic parallelogram must be a rectangle.