Theorem in a parallelogram prove that (i)the opposite sides are equal; (ii) the opposite angles are equal ;(iii) diagonals bisect each other.

A quadrilateral is a parallelogram if its opposite sides are equal.

A quadrilateral is parallelogram it its opposite sides are equal

In a parallelogram opposite sides are equal

Prove that vertically opposite angles are equal.

Theorem 8.2 : In a parallelogram, opposite sides are equal.

A quadrilateral whose all sides are equal, opposite angles are equal and the diagonals bisect each other at right angles is a __________.

A quadrilateral whose opposite sides and all the angles are equal is a

The converse of the above properties are also true i.e.(i) A quadrilateral is a parallelogram if its opposite sides are equal.(ii)A quadrilateral is a parallelogram if its opposite angles are equal.(iii) A quadrilateral is a parallelogram if it has one pair of opposite sides parallel and equal.(iv) A quadrilateral is a parallelogram if its diagonals bisect each other .

A quadrilateral is parallelogram if its opposite angles are equal.

The diagonals of a rectangle are equal and bisect each other