Prove that if two opposite angles and two opposite sides of any quadrilateral be parallel , then it is a parallelogram.

If the opposite sides of a quadrilateral are equal, prove that the quadrilateral is a parallelogram.

If each pair of opposite sides of a quadrilateral is equal, then prove that it is a parallelogram.

Prove that if both pairs of opposite sides of a quadrilateral are equal, then it is a parallelogram.

Apply vectors to prove that if a pair of opposite sides of quadrilateral are equal and parallel, then the figure is a parallelogram.

Theorem 8.3 : If each pair of opposite sides of a quadrilateral is equal, then it is a parallelogram.

Theorem 8.3 : If each pair of opposite sides of a quadrilateral is equal, then it is a parallelogram.

If two opposite sides of a cyclic quadrilateral are equal,then the other two sides are parallel.

If two opposite sides of a cyclic quadrilateral are equal; then the other two sides are parallel.

If two opposite sides of a cyclic quadrilateral are equal, then the other two sides are parallel.

If two pairs of opposite sides are equal in a quadrilateral then it is called …………….