Quadrilaterals

I am a quadrilateral in which the four sides are equal and the diagonals cross at right angles, but it is not a square. Which quadrilateral am I?

In a certain quadrilateral, two pairs of neighbouring sides are equal, but the opposite sides are not equal. Name the quadrilateral.

ABCD is a parallelogram with $\hat{C}=99^\circ$. Calculate, with reasons, the sizes of x and y.

ABCD is a parallelogram with $\hat{A}=68^\circ$. Calculate, with reasons, the sizes of x and y.

KLMN is a parallelogram with $\hat{K}=67^\circ$. Calculate, with reasons, the sizes of x and y.

ABCD is a parallelogram with $\hat{A}=71^\circ$. Calculate, with reasons, the sizes of x and y.

In a certain quadrilateral, the four sides are equal and the diagonals cross at right angles, but it is not a square. Name the quadrilateral.

PQRS is a parallelogram with $\hat{R}=107^\circ$. Calculate, with reasons, the sizes of x and y.

I am a quadrilateral in which exactly one pair of opposite sides is parallel. Which quadrilateral am I?

KLMN is a quadrilateral with $\hat{K}=97^\circ$, $\hat{L}=74^\circ$ and $\hat{M}=81^\circ$. Calculate, with a reason, the size of x.

PQRS is a quadrilateral with $\hat{P}=135^\circ$, $\hat{Q}=59^\circ$ and $\hat{R}=107^\circ$. Calculate, with a reason, the size of x.

I am a quadrilateral in which every angle is a right angle, yet two sides are longer than the other two. Which quadrilateral am I?