Area Of A Rectangle Formula

Area of a Rectangle Formula

In geometry, the area of a rectangle is the area covered by it in a two-dimensional plane. A rectangle is a type of quadrilateral, a two-dimensional object with four sides and four vertices. All four angles of the rectangle are right angles, or 90 degrees. The opposing sides of the rectangle are equal and parallel to one another. A parallelogram has opposite sides that are equal and parallel to one other, but the angles are not 90 degrees.

What is the Area of Rectangle?

The area of a rectangle is the space filled by its four edges or borders.

A rectangle’s area is determined by its side lengths. The formula for area is the product of the rectangle’s length and breadth. The circumference of a rectangle is equal to the sum of its four sides. As a result, the area of the rectangle is defined as the region contained by its perimeter. However, because all of the sides of a square are equal, the square’s area is equal to the square’s side length.

Area of rectangle = Length x Breadth

A = lb


l = Length

b = Breadth

Area of Rectangle Formula

The formula for calculating the area of a rectangle is based on its length and breadth. The area of a rectangle is computed by multiplying its width (or breadth) by its length. Only three-dimensional figures can have their lateral and total surface areas computed. We cannot compute for the rectangle since it is two-dimensional. Thus, the area of a rectangle may be calculated as:

The formula for the Area of a Rectangle
Area of a Rectangle A = l × b

The area of any rectangle is computed when its length and breadth are specified. The rectangle’s area may be calculated by multiplying its length and breadth.

How to Calculate Area of Rectangle?

Follow the steps below in order to find the area:

Step 1: Take note of the dimensions of length and breadth from the provided data.

Step 2: double the length and width values.

Step 3: Write your answer in square units.

Area of a Rectangle by Diagonal

The line that connects the opposing vertices of a rectangle’s diagonal is a straight line inside the rectangle. The rectangle has two diagonals, each of which is the same length. Using the Pythagoras theorem, one can determine a rectangle’s diagonal.

We know that the diagonal of a rectangle is calculated using the formula:

(Diagonal)2 = (Length)2 + (Width)2

From this,

(Length)2 = (Diagonal)2 – (Width)2


(Width)2 = (Diagonal)2 – (Length)2

Now, the area of rectangle = Length × Width

In this case, the width and length can be calculated using the formula,

Width = ⎷[(Diagonal)2 – (Length)2]


Length = ⎷[(Diagonal)2 – (Width)2]

Why Area of a Rectangle Is Length × Breadth?

Students should know why Length multiplied by Breadth is the Area Of A Rectangle Formula. One can calculate the rectangle’s area using its formula. A rectangle ABCD will have a diagonal AC drawn through it. The rectangle ABCD is clearly divided into two congruent triangles by the diagonal AC. The combined area of these two triangles equals the area of the rectangle.

Area of Rectangle ABCD = Area of Triangle ABC + Area of Triangle ADC

= 2 × (1/2 × Base × Height)

= AB × BC

= Length × Breadth

Solved Examples

Example 1: Calculate the area of the rectangle whose length is 18 cm and the width is 2 cm.



Length = 18 cm

Width = 2 cm

Area of a rectangle = Length × Width

18 × 2  = 36

So the area of rectangle = 36 cm2

Maths Related Formulas
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Pythagorean Theorem Formula Maclaurin Series Formula
Variance Formula Multiple Angle Formulas
Triangle Formula Point Of Intersection Formula
Area Formulas Sequence Formula
Derivative Formula Y Intercept Formula
Perimeter Of A Triangle Formula Volume Charge Density Formula

FAQs (Frequently Asked Questions)

1. What is the Area Of A Rectangle Formula?

The Area Of A Rectangle Formula is Length × Breadth.

2. Where to find solved examples on the Area Of A Rectangle Formula?

Solved examples on the Area Of A Rectangle Formula can be found on the Extramarks website and mobile application.

3. What is the Unit of Area of a Rectangle?

The area of a rectangle is expressed in square units.