When we talk about some plane figures, we think of their shape, region or boundary. We compare the objects on the basis of their size and area. We all know that we need some measure to compare them. And one such measure is its perimeter. All the objects that lie in a plane acquire some region of a flat surface. Perimeter is the distance around a closed figure. There are different geometrical shapes that exist namely square, rectangle, triangle, circle, etc. In this article, we will be focusing on understanding the perimeter of rectangle formula with some practical examples, its calculations, and units. Let us start our journey towards learning the topic!
Perimeter of Rectangle Formula
What is a Rectangle?
Let us first understand the shape and structure of a rectangle. A rectangle is a quadrilateral with four sides. It has straight lines on all 4 sides. The opposite sides of a rectangle are parallel and of equal length. Since a rectangle has four sides, it has four angles.
All angles of a rectangle are equal. It is an equiangular rectangle with four right angles which is 90 degrees. Another property of rectangle is that has two diagonals of equal length. Diagonals are a line that is drawn inside the rectangle connecting opposite corners or vertices and hence the diagonals of a rectangle are congruent.
When we go round a closed figure or body, along its boundary, for once, we cover a distance. The measure of the distance is the perimeter of the figure or body. Let us consider a rectangular field having length and breadth as 150 meters and 90 meters respectively.
To understand and measure the perimeter of the rectangular field, we travel along the boundary of the four sides of the field, starting from a point and ending at the same point. In doing so, we see that we cover a total distance of 480 meters. And hence, the perimeter of the rectangular field is 480 meters. While doing so, we observe that we measure the length and breadth, both, twice.
The perimeter of the Rectangle Formula
P = 2 × (l + b)
Where,
P | The perimeter of the rectangle |
l | Length of the rectangle |
b | Breadth of rectangle |
Solved Examples
Now that we have some clarity about the concept and meaning of the perimeter of the rectangle, let us try some examples to deepen our understanding of the subject.
Q: Shabana wants to put a lace border all around a rectangular table-cover 3 m long and 2 m wide. Calculate the length of the lace required by Shabana.
Ans: From the given information, length of the rectangular table-cover (l) = 3 m, breadth of the rectangular table-cover (b) = 2 m.
Shabana’s requirement is to put a lace border all around the table-cover.
Therefore, the length of the lace will be equal to the perimeter of the rectangular table – cover.
Now, perimeter of the rectangular table-cover = 2 × (length + breadth) = 2 × (l + b)
Perimeter of the rectangular table-cover = 2 × (3 m + 2 m) = 2 × 5 m = 10 m
Hence, the length of the lace required is 10 m.
I get a different answer for first example.
I got Q1 as 20.5
median 23 and
Q3 26