A special rhombus whose diagonals are equal in length is square.
Find which of the following are not true:
1. All the sides of a rhombus are always equal in length.
2. All the sides of a parallelogram are always equal in length.
3. Diagonals of a parallelogram are equal in length.
4. Diagonals of a square are equal in length.
5. Diagonals of a rectangle are equal in length.