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Last updated on September 26, 2025

Perimeter Area Formulas

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In geometry, understanding the formulas for perimeter and area is essential. The perimeter is the distance around a shape, while the area is the space within it. In this topic, we will learn the formulas for calculating the perimeter and area of various geometric figures.

Perimeter Area Formulas for US Students
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List of Perimeter and Area Formulas for

Calculating the perimeter and area helps us understand the dimensions of shapes. Let’s learn the formulas to calculate the perimeter and area of common geometric figures.

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Perimeter Formulas

The perimeter is the total distance around a two-dimensional shape.

 

It is calculated for different shapes as follows: 

 

  • Square: Perimeter = 4 × side 
     
  • Rectangle: Perimeter = 2 × (length + width) 
     
  • Triangle: Perimeter = sum of the lengths of all sides 
     
  • Circle: Perimeter (or Circumference) = 2 × π × radius
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Area Formulas

The area is the space occupied within a shape. Here are the area formulas for various shapes:

  • Square: Area = side × side 
     
  • Rectangle: Area = length × width
     
  • Triangle: Area = 1/2 × base × height 
     
  • Circle: Area = π × radius²
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Importance of Perimeter and Area Formulas

In math and real life, calculating the perimeter and area is crucial for various applications.

Understanding these formulas helps in: 

 

  • Determining the amount of material needed for construction or crafting 
     
  • Planning layouts for gardens, rooms, or any spatial arrangements 
     
  • Solving real-world problems involving land areas, fencing, and more
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Tips and Tricks to Memorize Perimeter and Area Formulas

Students can find math formulas tricky, but with some tips and tricks, they can master them: 

 

  • Use mnemonics such as "Perimeter is the Path" and "Area is the Arena" to differentiate between them 
     
  • Relate the shapes to real-life objects like a square to a chessboard or a rectangle to a book cover 
     
  • Create flashcards with formulas and practice rewriting them for quick recall
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Real-Life Applications of Perimeter and Area Formulas

Perimeter and area formulas are widely used in real life: 

 

  • In architecture, to estimate the amount of paint needed, area calculations are crucial 
     
  • In agriculture, to determine the fencing required around a field, perimeter is essential 
     
  • In flooring, to calculate the tiles needed for a room, area calculations are utilized
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Common Mistakes and How to Avoid Them While Using Perimeter and Area Formulas

Errors are common when calculating perimeter and area. Here are some mistakes and how to avoid them:

Mistake 1

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Confusing Perimeter and Area

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Students often confuse perimeter with area.

 

To avoid this, remember: Perimeter is the distance around, while area is the space within.

Mistake 2

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Incorrect Use of π in Circle Calculations

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Students sometimes use incorrect values for π.

 

Use 3.14 or 22/7 for calculations unless specified otherwise.

Mistake 3

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Forgetting to Use the Same Units

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Using different units can lead to errors.

 

Always convert measurements to the same unit before calculating.

Mistake 4

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Misidentifying Base and Height in Triangles

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Base and height must form a right angle in triangles.

 

Confusing these can result in incorrect area calculations.

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Examples of Problems Using Perimeter and Area Formulas

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Problem 1

Find the perimeter of a square with a side of 6 cm.

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The perimeter is 24 cm.

Explanation

Perimeter of a square = 4 × side = 4 × 6 cm = 24 cm.

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Problem 2

Calculate the area of a rectangle with a length of 8 m and a width of 3 m.

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The area is 24 m².

Explanation

Area of a rectangle = length × width = 8 m × 3 m = 24 m².

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Problem 3

A circle has a radius of 5 cm. Find its circumference.

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The circumference is 31.4 cm.

Explanation

Circumference of a circle = 2 × π × radius = 2 × 3.14 × 5 cm = 31.4 cm.

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Problem 4

Determine the area of a triangle with a base of 10 m and a height of 4 m.

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The area is 20 m².

Explanation

Area of a triangle = 1/2 × base × height = 1/2 × 10 m × 4 m = 20 m².

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FAQs on Perimeter and Area Formulas

1.What is the formula for the perimeter of a rectangle?

The formula for the perimeter of a rectangle is 2 × (length + width).

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2.How do you calculate the area of a circle?

The area of a circle is calculated using the formula: Area = π × radius².

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3.How is the perimeter of a triangle found?

The perimeter of a triangle is found by summing the lengths of all its sides.

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4.What is the perimeter of a square with side 4 m?

The perimeter of a square with side 4 m is 16 m.

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5.How can I find the area of a square?

The area of a square is found using the formula: side × side.

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Glossary for Perimeter and Area Formulas

  • Perimeter: The total distance around the edge of a geometric figure.

 

  • Area: The measure of space inside a two-dimensional shape.

 

  • Rectangle: A quadrilateral with opposite sides equal and all angles right angles.

 

  • Triangle: A polygon with three edges and three vertices.

 

  • Circle: A round shape with all points equidistant from the center.
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Jaskaran Singh Saluja

About the Author

Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.

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Fun Fact

: He loves to play the quiz with kids through algebra to make kids love it.

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