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Last updated on May 26th, 2025

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Square Root of 42

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If a number is multiplied by the same number, the result is a square. The inverse of the square is a square root. The square root is used in various fields such as vehicle design and finance. Here, we will discuss the square root of 42.

Square Root of 42 for Vietnamese Students
Professor Greenline from BrightChamps

What is the Square Root of 42?

The square root is the inverse of the square of the number. 42 is not a perfect square. The square root of 42 is expressed in both radical and exponential form.

In the radical form, it is expressed as √42, whereas (42)^(1/2) in the exponential form. √42 ≈ 6.4807, which is an irrational number because it cannot be expressed in the form of p/q, where p and q are integers and q ≠ 0.

square root of 42

Professor Greenline from BrightChamps

Finding the Square Root of 42

The prime factorization method is used for perfect square numbers. However, the prime factorization method is not used for non-perfect square numbers where long-division and approximation methods are used. Let us now learn the following methods:

 

  • Prime factorization method
  • Long division method
  • Approximation method
Professor Greenline from BrightChamps

Square Root of 42 by Prime Factorization Method

The product of prime factors is the prime factorization of a number. Now let us look at how 42 is broken down into its prime factors.

 

Step 1: Finding the prime factors of 42 Breaking it down, we get 2 x 3 x 7.

 

Step 2: Now we found the prime factors of 42. The second step is to make pairs of those prime factors. Since 42 is not a perfect square, the digits of the number can’t be grouped in pairs. Therefore, calculating 42 using prime factorization is not exact.

Professor Greenline from BrightChamps

Square Root of 42 by Long Division Method

The long division method is particularly used for non-perfect square numbers. In this method, we should check the closest perfect square number for the given number. Let us now learn how to find the square root using the long division method, step by step.

 

Step 1: To begin with, we need to group the numbers from right to left. In the case of 42, it is already a two-digit number, so we can consider it as 42.

 

Step 2: Now we need to find a number whose square is less than or equal to 42. We can say n as '6' because 6 x 6 = 36, which is less than 42. Now, the quotient is 6, and after subtracting 36 from 42, the remainder is 6.

 

Step 3: Add a decimal point to the quotient and bring down two zeros, making the new dividend 600.

 

Step 4: Double the current quotient to get 12, which will be part of our new divisor.

 

Step 5: Find a digit, let's say m, such that 12m x m is less than or equal to 600. Here, m is 4, since 124 x 4 = 496.

 

Step 6: Subtract 496 from 600, the difference is 104, and the quotient is 6.4.

 

Step 7: Continue this process to find more decimal places if needed.

 

So, the square root of √42 is approximately 6.48.

Professor Greenline from BrightChamps

Square Root of 42 by Approximation Method

The approximation method is another method for finding square roots. It is an easy method to find the square root of a given number. Now let us learn how to find the square root of 42 using the approximation method.

 

Step 1: Now we have to find the closest perfect square of √42. The smallest perfect square less than 42 is 36 and the largest perfect square greater than 42 is 49. √42 falls somewhere between 6 and 7.

 

Step 2: Now we need to apply the formula: (Given number - smaller perfect square) / (larger perfect square - smaller perfect square) (42 - 36) / (49 - 36) = 6/13 ≈ 0.46

 

Using the formula, we determined the decimal part of our square root. The next step is adding the value we got initially to the decimal number: 6 + 0.46 ≈ 6.46.

 

Thus, the square root of 42 is approximately 6.46.

Max Pointing Out Common Math Mistakes

Common Mistakes and How to Avoid Them in the Square Root of 42

Students often make mistakes while finding the square root, such as forgetting about the negative square root or skipping steps in methods like long division. Let's look at a few of these mistakes in detail.

Mistake 1

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Forgetting about the negative square root

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It is important to remind students that a number has both positive and negative square roots. However, we typically use only the positive square root in practical applications.

For example: √50 = 7.07, but there is also -7.07.

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Square Root of 42 Examples

Ray, the Character from BrightChamps Explaining Math Concepts
Max, the Girl Character from BrightChamps

Problem 1

Can you help Max find the area of a square box if its side length is given as √42?

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The area of the square is 42 square units.

Explanation

The area of the square = side^2. The side length is given as √42.

Area of the square = side^2 = √42 x √42 = 42.

Therefore, the area of the square box is 42 square units.

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Max, the Girl Character from BrightChamps

Problem 2

A square-shaped building measuring 42 square feet is built; if each of the sides is √42, what will be the square feet of half of the building?

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

21 square feet

Explanation

We can divide the given area by 2 since the building is square-shaped.

Dividing 42 by 2 = we get 21.

So half of the building measures 21 square feet.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 3

Calculate √42 x 5.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

Approximately 32.4

Explanation

The first step is to find the square root of 42, which is approximately 6.48.

The second step is to multiply 6.48 by 5.

So 6.48 x 5 = approximately 32.4.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 4

What will be the square root of (36 + 6)?

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The square root is 6.

Explanation

To find the square root, we need to find the sum of (36 + 6). 36 + 6 = 42, and then √42 = approximately 6.48.

Therefore, the square root of (36 + 6) is approximately ±6.48.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 5

Find the perimeter of the rectangle if its length ‘l’ is √42 units and the width ‘w’ is 38 units.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

We find the perimeter of the rectangle is approximately 88.96 units.

Explanation

Perimeter of the rectangle = 2 × (length + width)

Perimeter = 2 × (√42 + 38) = 2 × (6.48 + 38) = 2 × 44.48 = approximately 88.96 units.

Max from BrightChamps Praising Clear Math Explanations
Ray Thinking Deeply About Math Problems

FAQ on Square Root of 42

1.What is √42 in its simplest form?

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2.Mention the factors of 42.

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3.Calculate the square of 42.

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4.Is 42 a prime number?

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5.42 is divisible by?

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Professor Greenline from BrightChamps

Important Glossaries for the Square Root of 42

  • Square root: A square root is the inverse of a square. For example: 4^2 = 16 and the inverse of the square is the square root, that is √16 = 4.
     
  • Irrational number: An irrational number is a number that cannot be written in the form of p/q, where q is not equal to zero and p and q are integers.
     
  • Principal square root: A number has both positive and negative square roots, but the positive square root is typically used due to its applications in the real world.
     
  • Perfect square: A perfect square is a number that is the square of an integer. For example: 36 is a perfect square because it is 6^2.
     
  • Long division method: A mathematical procedure used to find the square root of non-perfect square numbers by dividing the number into pairs of digits.
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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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Max, the Girl Character from BrightChamps

Fun Fact

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

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