Quadrilaterals Properties | Parallelograms, Trapezium, Rhombus

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In this tutorial on basic geometry concepts, we cover the types and properties of quadrilaterals: Parallelogram, rectangle, square, rhombus, trapezium.


A quadrilateral is a simple closed figure with four sides.

Types of quadrilaterals

There are five types of quadrilaterals.

  • Parallelogram
  • Rectangle
  • Square
  • Rhombus
  • Trapezium

One common property of all quadrilaterals is that the sum of all their angles equals 360°.

Let us look into the properties of different quadrilaterals.


Parallelogram Properties

Properties of a parallelogram

  • Opposite sides are parallel and congruent.
  • Opposite angles are congruent.
  • Adjacent angles are supplementary.
  • Diagonals bisect each other and each diagonal divides the parallelogram into two congruent triangles.
  • If one of the angles of a parallelogram is a right angle then all other angles are right and it becomes a rectangle.

Important formulas of parallelograms

  • Area = L * H
  • Perimeter = 2(L+B)


Rectangle Properties

Properties of a Rectangle

  • Opposite sides are parallel and congruent.
  • All angles are right.
  • The diagonals are congruent and bisect each other (divide each other equally).
  • Opposite angles formed at the point where diagonals meet are congruent.
  • A rectangle is a special type of parallelogram whose angles are right.

Important formulas for rectangles

  • If the length is L and breadth is B, then

Length of the diagonal of a rectangle = √(L2 + B2)

  • Area = L * B
  • Perimeter = 2(L+B)


Squares Properties

Properties of a square

  • All sides and angles are congruent.
  • Opposite sides are parallel to each other.
  • The diagonals are congruent.
  • The diagonals are perpendicular to and bisect each other.
  • A square is a special type of parallelogram whose all angles and sides are equal.
  • Also, a parallelogram becomes a square when the diagonals are equal and right bisectors of each other.

Important formulas for Squares

  • If ‘L’ is the length of the side of a square then length of the diagonal = L √2.
  • Area = L2.
  • Perimeter = 4L


Rhombus Properties

Properties of a Rhombus

  • All sides are congruent.
  • Opposite angles are congruent.
  • The diagonals are perpendicular to and bisect each other.
  • Adjacent angles are supplementary (For eg., ∠A + ∠B = 180°).
  • A rhombus is a parallelogram whose diagonals are perpendicular to each other.

Important formulas for a Rhombus

If a and b are the lengths of the diagonals of a rhombus,

  • Area = (a* b) / 2
  • Perimeter = 4L


Trapezium Properties

Properties of a Trapezium

  • The bases of the trapezium are parallel to each other (MN ⫽ OP).
  • No sides, angles and diagonals are congruent.

Important Formulas for a Trapezium

  • Area = (1/2) h (L+L2)
  • Perimeter = L + L1 + L2 + L3

Summary of properties

Summarizing what we have learnt so far for easy reference and remembrance:

S.No. Property Parallelogram Rectangle Rhombus Square
1 All sides are congruent
2 Opposite sides are parallel and congruent
3 All angles are congruent
4 Opposite angles are congruent
5 Diagonals are congruent
6 Diagonals are perpendicular
7 Diagonals bisect each other
8 Adjacent angles are supplementary

Continue learning more about:
Properties of Lines and Angles
Properties and formulas of Circles
Types of Triangles and Properties

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  1. Sophie says:

    Do opposite sides in a quadrilateral have to be equal in order for it to have diagonals that are perpendicular?

    • Maryam says:

      Yes when sides on opposite are equal then only the diagnols perpendicularly bisect each other

      • K.K.Mukherjee says:

        It is not correct.The diagonals are perpendicular if and only if all the sides are equal as in the case of a rhombus or a square.
        The diagonals will be perpendicular also if the pairs of adjacent sides are equal as in the case of a kite

        • Mill Thread says:

          However, in a kite the diagonals are perpendicular but the diagonals are not congruent. In a rhombus, rectangle or square for it to have diagonals that is perpendicular and congruent all of its sides must be congruent. In the case of kite, of all of its sides are congruent it will become either a rhombus or a square.

        • Riya says:

          Thanks this was so helpful for me

    • Sid says:

      No all sides of a quadrilateral should be congruent for the diagonals to be perpendicular

    • Aaeesha says:

      Diagonal will be perpendicular only when all sides are equal not opposite sides.

    • Varsha sharma says:

      Hey mate
      Herez your answer

      If opposite sides would be equal in a quadrilateral still there is no any surity that the diagonals will be perpendicular

      For eg a paralleogram type quadrilateral whose
      opposite sides are equall but its doagonal
      Are not perpendicular.

      But if all the side became equal in a quadrilateral then therez the surity that the diagonal will be perpenficular

      Eg rhombus or square


    • Saif Ali Khan says:

      Actually not, for example kites dont have opposite sides equal but both of its diagonals are perpendicular.
      Simply we can say that if a quadrilateral have opposite sides equal then its diagonal will bisect each other.
      And if its adjacent sides are equal then they cut each other perpendicularly.
      Correct me if wrong

    • raju says:

      no all sides must be equal

  2. Piyush says:

    Are the measure of a pair of parallel sides in a trapezium equal?

  3. anonymous says:

    are the diagonals of the rectangles are congruent?
    how to proof it?

    • Anil says:

      Since the opposite sides of a rectangle are congruent, it’s diagonals are also congruent. This can be done by applying Pythagoras theorem..

    • Gurleen says:

      Take a triangle with common base from that dignols and made that triangle congruent by sas then both side will be equal by cpct

    • raju says:

      Yes we can proove it by sas method as diagnols bisect parrellelograms into 2 equal halves. and opp angles and sides are equal

  4. Grreshma says:

    If ab =33 bc =27 CD = 33 DA=21 area of quadrilateral ?

    • Simron says:

      Area of the quadrilateral = Area of rectangle + Area of Right angled triangle
      Length of the rectangle = 33cm
      Breadth of the rectangle = 21cm
      Area of rectangle = Length x Breadth
      = 33 x 21
      = 693 sq. cm
      Now in right angled triangle,
      Hypotenuse = 33cm
      Base = 6cm
      Therefore, the height of the triangle = Square root of (square of hypotenuse – square of base) [ By Pythagoras Theorem ]
      = Square root of(33 x 33 – 6 x 6)
      = Square root of 1053
      = 32.44cm
      Area of Right angled Triangle = 1/2 x base x height
      = 1/2 x (27-21) x 32.44
      = 1/2 x 6 x 32.44
      = 97.32 sq. cm

      So, Area of the quadrilateral = Area of rectangle + Area of Right angled triangle
      = 693 + 97.32
      = 790.32 sq. cm

    • Saurabh says:

      Why are you asking because it is quite easy?

      You know that when the heights of quadrilateral are given which will perpendicular to any one of diagonal then fomula for area is given by

  5. Kevin says:

    What are the names of the three different quadrilaterals with two congruent

  6. Ajaz says:

    Explain the sum of properties of quadrilateral is 360 degree.

  7. VUSI says:

    Are diagonals the bisectors of angles in a quadrilateral or parallelogram?

  8. Kunal says:

    Is parallelogram a trapezium?

  9. Bodhisatya says:

    I have an query on trapezium
    If a angle of a trapezium is 90°then what is it called

  10. nabaah says:

    squares are my favourite type of quadrilaterals

  11. Vasant Barve says:

    Why so much confusion 1) Square, Rhombus & kite have the diagonals at right angles to each other.

  12. Ysa says:

    But what do you call a quadrilateral that is not a parallelogram with one diagonal that divides the quadrilateral into two congruent triangles

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