A square is a parallelogram with four congruent sides and four right angles.


Because it is a parallelogram, all the properties of a parallelogram apply to the square. It is also a rectangle because it has four right angles and all of the properties of a rectangle apply to a square.  It is also a rhombus because it has four congruent sides and all of the properties of a rhombus apply to a square.  Therefore, all the properties listed below are true for a square:

    • All four sides are equal in length.
    • All four angles are 90o
    • Opposite sides are parallel.
    • Diagonals are equal in length.
    • Diagonals are perpendicular.
    • Diagonals bisect each other.
    • Diagonals bisect the angles of the square.

*Note: All squares are a rhombus, rectangle and parallelogram, but not all rhombuses, rectangles or parallelograms are squares.

All of the properties that apply to a square, can be used to find unknown quantities.  There is a lot of information about the parts of a square, so be careful to apply the correct property.