BrightChamps Logo
Login
Creative Math Ideas Image
Live Math Learners Count Icon101 Learners

Last updated on May 26th, 2025

Math Whiteboard Illustration

Square Root of 721

Professor Greenline Explaining Math Concepts

If a number is multiplied by itself, the result is a square. The inverse of squaring a number is finding its square root. The square root is used in various fields, including vehicle design and finance. Here, we will discuss the square root of 721.

Square Root of 721 for US Students
Professor Greenline from BrightChamps

What is the Square Root of 721?

The square root is the inverse of squaring a number. 721 is not a perfect square. The square root of 721 is expressed in both radical and exponential form. In radical form, it is expressed as √721, whereas (721)^(1/2) in exponential form. √721 ≈ 26.85144, 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.

Professor Greenline from BrightChamps

Finding the Square Root of 721

The prime factorization method is typically used for perfect square numbers. However, for non-perfect square numbers, methods like the long division method and approximation method are used. Let us now learn the following methods: 

 

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

Square Root of 721 by Prime Factorization Method

Prime factorization involves expressing a number as the product of its prime factors. However, since 721 is not a perfect square, finding its square root using prime factorization is not straightforward.

 

Step 1: Finding the prime factors of 721

 

Breaking it down, we get 7 × 103: 7^1 × 103^1

 

Step 2: Since 721 is not a perfect square, the digits of the number can’t be grouped in pairs that result in a perfect square. Therefore, calculating √721 using prime factorization is not possible.

Professor Greenline from BrightChamps

Square Root of 721 by Long Division Method

The long division method is particularly used for non-perfect square numbers. This method involves estimating the square root of a number by dividing it into pairs of digits. Let us now learn how to find the square root using the long division method, step by step.

 

Step 1: Group the numbers from right to left. For 721, we have groups 72 and 1.

 

Step 2: Find a number whose square is less than or equal to 72. Let n be 8, since 8 × 8 = 64 ≤ 72. The quotient is 8, and the remainder is 72 - 64 = 8.

 

Step 3: Bring down 1, making the new dividend 81. Double the quotient, 8, to get 16, which is part of the new divisor.

 

Step 4: Find a number x such that (160 + x) × x ≤ 81. Let x be 0, since 160 × 0 = 0 ≤ 81.

 

Step 5: Since the remainder is still 81, add a decimal point and two zeroes, making the new dividend 8100.

 

Step 6: Using 1600 as the new divisor, find a digit y such that (1600 + y) × y ≤ 8100. Let y be 5, since 1605 × 5 = 8025 ≤ 8100.

 

Step 7: Subtract 8025 from 8100 to get a new remainder of 75. The quotient is now 26.85.

 

Step 8: Continue these steps until the desired precision is reached.

Professor Greenline from BrightChamps

Square Root of 721 by Approximation Method

The approximation method is another way to find square roots. This method involves estimating the square root by identifying perfect squares closest to the number. Let us learn how to find the square root of 721 using the approximation method.

 

Step 1: Identify perfect squares around √721. The closest perfect square less than 721 is 676 (26^2), and the closest perfect square greater than 721 is 729 (27^2). √721 falls between 26 and 27.

 

Step 2: Use linear interpolation to approximate the square root. Using the formula: (Given number - smaller perfect square) / (larger perfect square - smaller perfect square) (721 - 676) / (729 - 676) = 45 / 53 ≈ 0.849 Adding this to the base of 26 gives 26 + 0.849 = 26.849, so the approximate square root of 721 is ≈ 26.85.

Max Pointing Out Common Math Mistakes

Common Mistakes and How to Avoid Them in the Square Root of 721

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

Mistake 1

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Forgetting about the negative square root

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

Students should be aware that a number has both positive and negative square roots. However, typically only the positive root is used for practical purposes.

For example: √49 = 7, but there is also -7, which should not be forgotten.

Max from BrightChamps Saying "Hey"

Square Root of 721 Examples

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

Problem 1

Can you help Alex find the area of a square box if its side length is given as √721?

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

The area of the square is approximately 721 square units.

Explanation

The area of a square is calculated by squaring the side length.

The side length is given as √721.

Area = side^2 = √721 × √721 = 721.

Therefore, the area of the square box is approximately 721 square units.

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

Problem 2

A square-shaped garden measures 721 square feet; if each side is √721, what is the area of half of the garden?

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

360.5 square feet

Explanation

To find half the area of the garden, divide the total area by 2.

Half of 721 square feet = 721 / 2 = 360.5 square feet.

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

Problem 3

Calculate √721 × 5.

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

Approximately 134.257

Explanation

First, find the square root of 721, which is approximately 26.851.

Multiply this by 5: 26.851 × 5 ≈ 134.257.

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

Problem 4

What is the square root of (721 + 4)?

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

The square root is approximately 27.

Explanation

First, find the sum of 721 + 4, which is 725.

Since 725 is close to 729, which is 27^2, the square root of 725 is approximately 27.

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

Problem 5

Find the perimeter of a rectangle if its length 'l' is √721 units and the width 'w' is 50 units.

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

The perimeter of the rectangle is approximately 153.702 units.

Explanation

Perimeter of a rectangle = 2 × (length + width).

Perimeter = 2 × (√721 + 50) = 2 × (26.851 + 50) = 153.702 units.

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

FAQ on Square Root of 721

1.What is √721 in its simplest form?

Math FAQ Answers Dropdown Arrow

2.Mention the factors of 721.

Math FAQ Answers Dropdown Arrow

3.Calculate the square of 721.

Math FAQ Answers Dropdown Arrow

4.Is 721 a prime number?

Math FAQ Answers Dropdown Arrow

5.721 is divisible by?

Math FAQ Answers Dropdown Arrow

6.How does learning Algebra help students in United States make better decisions in daily life?

Math FAQ Answers Dropdown Arrow

7.How can cultural or local activities in United States support learning Algebra topics such as Square Root of 721?

Math FAQ Answers Dropdown Arrow

8.How do technology and digital tools in United States support learning Algebra and Square Root of 721?

Math FAQ Answers Dropdown Arrow

9.Does learning Algebra support future career opportunities for students in United States?

Math FAQ Answers Dropdown Arrow
Professor Greenline from BrightChamps

Important Glossaries for the Square Root of 721

  • Square root: A square root of a number is a value that, when multiplied by itself, gives the original number. Example: The square root of 25 is 5, as 5 × 5 = 25.

 

  • Irrational number: An irrational number cannot be written as a simple fraction, meaning its decimal form is non-repeating and non-terminating. Example: √2 is irrational.

 

  • Principal square root: The principal square root is the non-negative root of a number. For example, the principal square root of 9 is 3.

 

  • Perfect square: A perfect square is a number that is the square of an integer. Example: 36 is a perfect square because it is 6^2.

 

  • Long division method: A technique used to find the square root of a number by breaking it down into simpler steps, often used for non-perfect squares.
Professor Greenline from BrightChamps

About BrightChamps in United States

At BrightChamps, we understand algebra is more than just symbols—it’s a gateway to endless possibilities! Our goal is to empower kids throughout the United States to master key math skills, like today’s topic on the Square Root of 721, with a special emphasis on understanding square roots—in an engaging, fun, and easy-to-grasp manner. Whether your child is calculating how fast a roller coaster zooms through Disney World, keeping track of scores during a Little League game, or budgeting their allowance for the latest gadgets, mastering algebra boosts their confidence to tackle everyday problems. Our hands-on lessons make learning both accessible and exciting. Since kids in the USA learn in diverse ways, we customize our methods to suit each learner’s style. From the lively streets of New York City to the sunny beaches of California, BrightChamps brings math alive, making it meaningful and enjoyable all across America. Let’s make square roots an exciting part of every child’s math adventure!
Math Teacher Background Image
Math Teacher Image

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.

Math Teacher Fun Facts Image
Max, the Girl Character from BrightChamps

Fun Fact

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

INDONESIA - Axa Tower 45th floor, JL prof. Dr Satrio Kav. 18, Kel. Karet Kuningan, Kec. Setiabudi, Kota Adm. Jakarta Selatan, Prov. DKI Jakarta
INDIA - H.No. 8-2-699/1, SyNo. 346, Rd No. 12, Banjara Hills, Hyderabad, Telangana - 500034
SINGAPORE - 60 Paya Lebar Road #05-16, Paya Lebar Square, Singapore (409051)
USA - 251, Little Falls Drive, Wilmington, Delaware 19808
VIETNAM (Office 1) - Hung Vuong Building, 670 Ba Thang Hai, ward 14, district 10, Ho Chi Minh City
VIETNAM (Office 2) - 143 Nguyễn Thị Thập, Khu đô thị Him Lam, Quận 7, Thành phố Hồ Chí Minh 700000, Vietnam
Dubai - BrightChamps, 8W building 5th Floor, DAFZ, Dubai, United Arab Emirates
UK - Ground floor, Redwood House, Brotherswood Court, Almondsbury Business Park, Bristol, BS32 4QW, United Kingdom