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472 LearnersLast updated on August 5, 2025

The square root is the inverse of the square of the number. 7921 is a perfect square. The square root of 7921 is expressed in both radical and exponential form. In radical form, it is expressed as √7921, whereas (7921)^(1/2) in exponential form. √7921 = 89, which is a rational number because it can be expressed in the form of p/q, where p and q are integers and q ≠ 0.
The prime factorization method is used for perfect square numbers. However, other methods like the long-division method and approximation method can also be used. Let us now learn the following methods:
The product of prime factors is the prime factorization of a number. Now let us look at how 7921 is broken down into its prime factors.
Step 1: Finding the prime factors of 7921 Breaking it down, we get 89 x 89: 89²
Step 2: Now we have found the prime factors of 7921. The second step is to make pairs of those prime factors. Since 7921 is a perfect square, the digits of the number can be grouped in pairs. Therefore, calculating 7921 using prime factorization gives us √7921 = 89.


The long division method is particularly used for both perfect and non-perfect square numbers. 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 7921, we group it as 79 and 21.
Step 2: Now we need to find n whose square is less than or equal to 79. We can say n as ‘8’ because 8 x 8 = 64 is less than 79. Now the quotient is 8, after subtracting 64 from 79 the remainder is 15.
Step 3: Let us bring down 21, making the new dividend 1521. Add the old divisor with the same number 8 + 8, we get 16 which will be our new divisor.
Step 4: The new divisor will be 16n. Now we need to find the value of n such that 16n x n ≤ 1521. Let us consider n as 9, now 169 x 9 = 1521.
Step 5: Subtract 1521 from 1521, the remainder is 0, and the quotient is 89. The square root of √7921 is 89.
The approximation method is another method for finding square roots, it is an easy method to find the square root of a given number. However, since 7921 is a perfect square, the approximation method is not necessary, as the exact answer is already known: √7921 = 89.
Students do make mistakes while finding the square root, such as forgetting about the negative square root. Skipping long division methods, etc. Now let us look at a few of those mistakes that students tend to make in detail.
Can you help Max find the area of a square box if its side length is given as √7921?
The area of the square is 7921 square units.
The area of the square = side². The side length is given as √7921. Area of the square = side² = √7921 x √7921 = 89 × 89 = 7921. Therefore, the area of the square box is 7921 square units.
A square-shaped building measuring 7921 square feet is built; if each of the sides is √7921, what will be the square feet of half of the building?
3960.5 square feet
We can just divide the given area by 2 as the building is square-shaped. Dividing 7921 by 2, we get 3960.5. So half of the building measures 3960.5 square feet.
Calculate √7921 x 5.
445
The first step is to find the square root of 7921, which is 89. The second step is to multiply 89 with 5. So 89 x 5 = 445.
What will be the square root of (13456 + 7921)?
The square root is 145
To find the square root, we need to find the sum of (13456 + 7921). 13456 + 7921 = 21377, and then √21377 ≈ 145. Therefore, the square root of (13456 + 7921) is approximately ±145.
Find the perimeter of the rectangle if its length ‘l’ is √7921 units and the width ‘w’ is 38 units.
The perimeter of the rectangle is 254 units.
Perimeter of the rectangle = 2 × (length + width). Perimeter = 2 × (√7921 + 38) = 2 × (89 + 38) = 2 × 127 = 254 units.

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






