How to Find Perimeter

To begin with a Perimeter’s concept, we have known every aspect of it. In addition, we shall also know how to find Perimeter. However, the Perimeter comes from various shapes, like- rectangle, square, circle, Triangle, etc. Other than that, it is more like a continuous line forming that surrounds the whole boundary of any geometrical figure. 

Well, there are different names for a perimeter. They are- outer edge, outside, or circumference. Moreover, the Perimeter of a shape tends to be an instrument that measures the extent of a field of vision. Be it one-dimensional length or two-dimensional shape, the concept of the Perimeter is inevitable everywhere. 

In brief, we got to know some facts about the Perimeter. But still, there is more to know about it, such as formula, method, etc. To figure out all of them, keep continuing here.

What is Perimeter? 

Unless we do not get to a shape’s perimeter, it will not be possible to judge its total aspects. Besides, knowing the perimeter’s definition cannot be avoided too.

First of all, we have to know what the Perimeter is. A path that outlines or surrounds a shape of one dimension or two dimensions is known as Perimeter. Or you can say, Perimeter refers to the circumference of an ellipse or circle. 

While calculating a shape’s Perimeter, you will need to follow some practical applications too. On a note, a calculated perimeter is similar to a fence that surrounds a garden or yard. Contrastingly, a circle’s or wheel’s circumstance tells us to what extent it can go in one revolution. 

When you see a spool’s string, keep in mind that it is related to its Perimeter.

Formulas of Perimeter 

Coming to the formulas of the Perimeter, they vary according to shape. Now let us go through them by the given table.

Circle2πr = πd or C = 2πr
Square or Rhombus4a
Rectangle 2(1+w)
Equilateral Polygon n × a
Regular Polygon(number of sides) × (length of one side).
General Polygona1 + a2 + a3 + ……. + an

How to Solve Perimeter 

How to Find Perimeter

Today we’re going to solve the Arian

The perimeter of a rectangle. Usually, the rectangle has two sets of congruent sides

or equal sides. Suppose a rectangle is 12, then the top is also 12. If another side is 7, then its opposite Side is also 7. So to solve the area of a rectangle, we need to think of the formula. And the formula consists of length and width. Thus, we are to find the inside of areas. So the length is

going to be 12 times the width which is 7.

When we will do 12 times 7, we will get 84 to meet the label that is in centimeters. So the answer is 84 square centimeters. The Perimeter To find the perimeter member is just adding all the sides. So if you see a rectangle has one, two, three, four sides. Hence, we are going to add four numbers and add 12 plus 12 and then 7 plus 7  

When we add all those sides, you get 38 centimeters. So our Perimeter is 38 centimeters.

How to Find Perimeter of a Rectangle

To find the perimeter of a rectangle, we will first have to add all sides of it. For example, a rectangle has two sides of length, i.e., 12 cm, and two sides of breadth, i.e., 7 cm. If you see, the Perimeter of this rectangle will be-

12+12+7+7 = 38

A rectangle Coming to another example has height and width; you can easily find all four sides. Just multiply both height and width of the rectangle and add their results. Such as, ( 2.9 ) + ( 2.7 ) = 32

How to Find Perimeter of a Triangle 

All in all, the Perimeter of a triangle is inevitable after adding all three sides of it. Well, in the case of a triangle’s Perimeter, you will have to apply the below formula-

The Perimeter of Triangle = Sum of all three sides

Here, you will have to include all units of the Triangle, which will be measured in centimeters. Suppose a triangle has three sides, e.g., a, b, and c. Then the Perimeter of the Triangle will be = a + b + c

In this way, you can easily find out the Perimeter of a rectangular-shaped object or space. In the same way, getting other figures’ Perimeter is simpler. Just follow their formulas, and getting their Perimeter will be a cakewalk for you.

How to Find Perimeter of a Circle

As mentioned before, the Perimeter of a circle is called the circumference. Usually, it is presented as capital C. For instance, you can calculate the Perimeter of a circle with 3.14 × d or Pi × diameter = C. 

Now you must be thinking about what Pi is. Anyways, Pi is the result you will get after dividing a circle’s circumference by the diameter. Although the measurement of diameter and circumference of a circle differs sometimes, its Pi will always be the same. However, in every calculation, the pi tends to be infinite, like- 3.1415926 ….. But to make it easier, it can be decreased in number, i.e., 3.14.

How to Find Perimeter of a Square 

Well, we all know that the Perimeter defines the surrounding of a length in one or two dimensions. Similarly, the Perimeter of a square shape can be identified after adding all sides of length in a square. 

Coming to the formula of square’s Perimeter will express it as- 

(P) The perimeter of square = 4 × all sides

Example: A square has four sides, where each Side is 3 cm. Now you are to find its Perimeter. 

Answer: 4 × all sides = 4 × 3 cm = 12 cm.

From the above, we already know how to calculate the perimeter of a square with the help of a formula. But sometimes, the sides of squares are not given. At that time, we will need to work with two details. They are-

  1. Area of Square
  2. Square’s length of diagonal

We know, the sides of a square or regular polygon are always the same. Besides, the angles of the square are 90 degrees. That time, we will have to apply the Pythagorean theorem, i.e., Diagonal = Side.√2

Hence, we can also determine the sides of square in-.

Side of square = √2(Diagonal/2)


Diagonal = Side.√2

Also, we know, 

Perimeter of square = 4 x all sides = 4 x √2(Diagonal/2)


Perimeter of square = 2√2(Diagonal) units.

For example, A square has a diagonal length of 10 cm. Now, find its Perimeter. 

Solution: To find the perimeter of the square, which has a diagonal length of 10 cm, we will need to apply the given formula. 

Perimeter = 2√2(Diagonal) 

Thus, 2√2(10) = 20√2 cm.

Frequently Asked Questions 

Is There Any Rule for Perimeter? 

Yes, there are some obvious rules we need to follow while finding the Perimeter of a shape. Suppose we are going to find a rectangle’s Perimeter. At that time, add the 4 sides sequentially. Whereas we will get to see only the height and width are sometimes given. The height of a rectangle is the summation of two sides, and width is the summation of the other two sides. In such situations, add the height and width of that rectangle, and you will easily get its Perimeter. 

Does a Perimeter Get Affected by Shape?

Yes, a perimeter gets affected by shape. Or whenever the length and breadth of a figure varies, that also significantly impacts its Perimeter. Besides, the Perimeter of a shape refers to the total length of an edge and that surface area.

Where is Perimeter Used Often?

There are lots of substances where we mostly see the use of Perimeter. For example, you got some Christmas lights that are fenced around your backyard garden. Furthermore, a soccer field’s boundary length or a crochet’s length needs a table mat to cover its border. 

What Characteristics Does a Perimeter Have?

All in all, a two-dimensional shape’s Perimeter means the total distance around its shape. While in some figures, which have straight sides like square, triangle, or polygon. Consequently, the Perimeter will be apparent after adding all the sides of length.


To sum up, we can say Perimeter plays a great role in identifying a shape in total. Likewise, a shape of a garden or yard holds a certain shape, after all. On the flipping side, every geometrical figure is surrounded by an outline. And getting that figure after doing some calculations is none other than a perimeter. To find it, we will have to know how to find Perimeter. Hopefully, the above article could give you a prescribed idea about figuring out any shape’s Perimeter. Mainly, we get to see shapes like rectangles, squares, circles, triangles. On that note, getting the Perimeter of all these shapes can be easier for you from the above discussion. Best of luck.

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