In Geometry, the shapes or objects are classified based on the number of sides. The different classification of shapes are:
 Triangle ( 3sides)
 Quadrilateral (4sides)
 Pentagon (5sides)
 Hexagon (6sides)
 Heptagon (7sides)
 Octagon (8sides) and so on.
In this article, we are going to discuss “Quadrilaterals” in detail.
Table of Contents:
Quadrilateral Definition
A quadrilateral is a plane figure that has four sides or edges, and also have four corners or vertices. Quadrilaterals will typically be of standard shapes with four sides like rectangle, square, trapezoid, and kite or irregular and uncharacterized as shown below:
Types of Quadrilaterals
There are many types of quadrilaterals. As the word ‘Quad’ means four, all these types of a quadrilateral have four sides, and the sum of angles of these shapes is 360 degrees.

 Trapezium
 Parallelogram
 Squares
 Rectangle
 Rhombus
 Kite
Another way to classify the types of quadrilaterals are:
 Convex Quadrilaterals: Both the diagonals of a quadrilateral are completely contained within a figure.
 Concave Quadrilaterals: At least one of the diagonals lies partly are entirely outside of the figure.
 Intersecting Quadrilaterals: Intersecting quadrilaterals are not simple quadrilaterals in which the pair of nonadjacent sides intersect. This kind of quadrilaterals are known as selfintersecting or crossed quadrilaterals
The images of these quadrilaterals are given below:
Quadrilateral Formula
Area of the quadrilateral is the total space occupied by the figure. The area formula for the different quadrilaterals are given below:
Area of a Parallelogram  Base x Height 
Area of a Rectangle  Length x Width 
Area of a Square  Side x Side 
Area of a Rhombus  (1/2) x Diagonal 1 x Diagonal 2 
Area of a Kite  1/2 x Diagonal 1 x Diagonal 2 
Quadrilateral Properties
Let us understand in a better way with the help of an example:
 Four sides: AB, BC, CD, and DA
 Four vertices: Points A, B, C, and D
 Four angles: ∠ABC, ∠BCD, ∠CDA, and ∠DAB
 ∠A and ∠B are adjacent angles
 ∠A and ∠C are the opposite angles
 AB and CD are the opposite sides
 AB and BC are the adjacent sides
A quadrilateral is a 4sided plane figure. Below are some important properties of quadrilaterals :
 Every quadrilateral has 4 vertices, 4 angles, and 4 sides
 The total of its interior angles = 360 degrees
Square Properties
 All the sides of the square are of equal measure
 The sides are parallel to each other
 All the interior angles of a square are at 90 degrees (i.e., right angle)
 The diagonals of a square perpendicular bisect each other
Rectangle Properties
 The opposite sides of a rectangle are of equal length
 The opposite sides are parallel to each other
 All the interior angles of a rectangle are at 90 degrees.
 The diagonals of a rectangle bisect each other.
Rhombus Properties
 All the four sides of a rhombus are of the same measure
 The opposite sides of the rhombus are parallel to each other
 The opposite angles are of the same measure
 The sum of any two adjacent angles of a rhombus is equal to 180 degrees
 The diagonals perpendicularly bisect each other
Parallelogram Properties
 The opposite side of the parallelogram are of the same length
 The opposite sides are parallel to each other
 The diagonals of a parallelogram bisect each other
 The opposite angles are of equal measure
 The sum of two adjacent angles of a parallelogram is equal to 180 degrees
Properties of Trapezium
 Only one pair of the opposite side of a trapezium is parallel to each other
 The two adjacent sides of a trapezium are supplementary (180 degrees)
 The diagonals of a trapezium bisect each other in the same ratio
Properties of Kite
 The pair of adjacent sides of a kite are of the same length
 The largest diagonal of a kite bisect the smallest diagonal
 Only one pair of opposite angles are of the same measure.
Summary of Quadrilateral Properties
Square  Rectangle  Rhombus  Parallelogram  Trapezium  
All sides are equal  Yes  No  Yes  No  No 
Opposite sides are parallel  Yes  Yes  Yes  Yes  Yes 
Opposite sides are equal  Yes  Yes  Yes  Yes  No 
All the angles are of the same measure  Yes  Yes  No  No  No 
Opposite angles are of equal measure  Yes  Yes  Yes  Yes  No 
Diagonals bisect each other  Yes  Yes  Yes  Yes  No 
Two adjacent angles are supplementary  Yes  Yes  Yes  Yes  No 
Notes on Quadrilateral
 A quadrilateral is a trapezoid or a trapezium if 2 of its sides parallel to each other.
 A quadrilateral is a parallelogram if 2 pairs of sides parallel to each other.
 Squares and Rectangles are special types of parallelograms. Below are some special properties.– All internal angles are of “right angle” (90 degrees).– Each figure contains 4 right angles.– Sides of a square are of the same length (all sides are congruent) – Opposite sides of a rectangle are same.– Opposite sides of a rectangle and square are parallel.
 A quadrilateral is a rhombus, if
 All the sides are of equal lengthSpecified 2 pairs of sides are parallel to each other.
 A kite is a special sort of quadrilateral, in which 2 pairs of adjacent sides are equal to each other.
Quadrilaterals Examples
Example 1: What is the base of a rhombus, if its area is 40 square units and the height is 8 units?
Solution:
Given,
Area = 40 square units
Height = 8 units
Area of rhombus = Base × Height
40 = Base × 8
Base = 40/8 = 5 units
Example 2: If 15 metre and 6 metres are diagonal lengths of a kite, then what is its area?
Solution: Given, diagonal 1 = 15 metre and diagonal 2 = 6 metre. So, the area is simply calculated as, (1/2)(15×6) = 45 m^{2}.
You can practice more examples of Quadrilateral using the quadrilateral worksheet.
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Frequently Asked Questions
What are Quadrilaterals and its types?
A quadrilateral can be defined as a plane figure having 4 sides. There are mainly 6 types of quadrilaterals which are:
 Trapezium
 Parallelogram
 Rectangle
 Rhombus
 Square
 Kite
Apart from these 6 types, a quadrilateral can also be classified as:
 Concave quadrilaterals
 Convex quadrilaterals
 Intersecting quadrilaterals
What is a convex and concave quadrilateral?
A convex quadrilateral can be defined as a quadrilateral whose both the diagonals are completely contained within the figure. On the other hand, a concave quadrilateral is a quadrilateral which is having at least one diagonal that lies partly or entirely outside of the figure.
What is the sum of the interior angles of a quadrilateral?
The sum of all the interior angles of a quadrilateral is 360°.
What are the three attributes of a quadrilateral?
The three important attributes of a quadrilateral are:
Four sides
Four Vertices
The sum of the interior angles should be equal to 360 degrees.
How to find the perimeter of a quadrilateral?
The perimeter of a quadrilateral can be determined by adding the side length of all the four sides.
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