### Theory:

A rectangle is called a square whose adjacent sides are equal.
Now we are going to define a square $$ABCD$$ as a quadrilateral is a rectangle whose sides are in the same measure.

Thus, if $$ABCD$$ is a rectangle then $$AB = BC = CD = AD$$ and $$AB || CD$$ and $$BC || AD$$.

Important!
Rhombus is a special case of kite. Note that the sides of a rhombus are all of the same length; this is not the case with the kite.

A rectangle has all the properties of a parallelogram.
In a square, the following properties are true:
1. The opposite sides are parallel.
2. All the four sides are in equal measure.
3. The interior angles of the square is $$90°$$.
4. The diagonals are equal in measure and perpendicular bisector of each other.
5. The adjacent angles are supplementary.