Area of Rectangle

In this page area of rectangle we are going to see how to find the area of any rectangle. We have given formulas, example problems and practical problems to understand the practical use of this topic.

Formula:

Area of rectangle  =  L x B

Here L represents length of the rectangle and B represents the breadth of the rectangle.

Example 1:

Find the area of the rectangle whose length is 15 cm and breadth is 20 cm.

Solution:

Area of-rectangle  =  L x B

Here length (l) = 15 cm and breadth = 20 cm

                                        = 15 x 20       

                                        = 300 cm²


Example 2:

Find the area of the rectangle having the diagonal is measuring 13 cm and length measuring 12 cm.

Solution:

To find the area of any rectangle first we need the measurement of length and breadth. Here length is given that is 9 cm and instead of breadth we have diagonal length. To find the breadth of the rectangle first let us consider the below rectangle ABCD.

In triangle ACB right angled at B. The side which is opposite to 90 degree is called hypotenuse side. By using Pythagorean theorem

AC² = AB² + BC²

13² = 12² + BC²

169 = 144 + BC²

169 - 144 = BC²

25 = BC²

BC = √25

BC = √5 x 5

BC = 5

Now we have the breadth of the rectangle 5 cm.

Area of the rectangle = Length x Breadth

                             = 12 x 5

                             = 60 cm²


Example 3:

The length and breadth of the rectangle are in the ratio 5:2 .If the area of the rectangle is measuring 147 cm². Then find the length and breadth of the rectangle.

Solution:

Let 5x and 2x be the length and breadth of the rectangle respectively.

Area of the rectangle = 147 cm²

Length x breadth = 147

            5x x 2x = 147

                 7x² = 147

                  x² = 147/7

                  x² = 21

                  x = √21   

     Length = 5x = 5√21 cm

     Breadth = 2x = 2√21 cm    area of rectangle


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