In figure—

Let PQRS be the Parallelogram.

- PQ = RS & PR = QS (side length)
- QS ≠ PR. ( diagonals are not equal)
- PQ || RS and PS || QR.
- ∠SPQ = ∠QRS and ∠PQR = ∠RSP

Note : Parallelogram is a Rectangle if and only if all angles right angle.

Note : Diagonals are bisect to each other in all case.

To Prove :

- Rectangle :

Opposite sides and diagonals are equal.

2. Square :

All sides and diagonals are equal.

3. Rhombus :

All sides are equal and diagonals are not equal.

4. Paralellogram :

Opposite sides are equal and diagonals are not equal.