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127 LearnersLast updated on December 15, 2025

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 concept extends into complex numbers when dealing with negative numbers. Here, we will discuss the square root of -12.
The square root is the inverse of the square of the number.
Since -12 is a negative number, its square root is not a real number. Instead, it is expressed in terms of imaginary numbers.
The square root of -12 can be expressed as √(-12) = √(12) × √(-1) = 2√3i, where 'i' is the imaginary unit, defined as √(-1).
To find the square root of -12, we need to use complex numbers.
The square root of -12 can be expressed in terms of its real and imaginary components.
Here, we will explore the method to derive the square root of -12:
1. Identify the real square root of the positive component, 12.
2. Multiply the result by the imaginary unit 'i' to account for the negative sign.
The prime factorization method is used to simplify the positive part of the number before introducing the imaginary unit.
Let's explore how this works with -12:
Step 1: Factorize the positive component, 12, into its prime factors. Breaking it down, we get 2 × 2 × 3 = 2² × 3.
Step 2: Express the square root of 12. √12 = √(2² × 3) = 2√3.
Step 3: Introduce the imaginary unit for the negative sign. √(-12) = √12 × √(-1) = 2√3 × i = 2√3i.


The long division method is typically used for non-perfect square real numbers, but when dealing with negative numbers, we need to use complex number operations.
Therefore, the long division method is not applicable directly for negative numbers like -12.
Instead, we use the concept of imaginary numbers as previously discussed.
While the approximation method is used for real numbers, for complex numbers such as the square root of -12, we rely on the direct calculation involving imaginary numbers.
The approximation method is not applicable here since the result involves 'i', the imaginary unit.
Students often make mistakes when dealing with square roots of negative numbers.
Let us look at a few common mistakes and how to avoid them.
What is the square root of -12 expressed in terms of 'i'?
The square root of -12 is 2√3i.
Since -12 is a negative number, its square root involves the imaginary unit 'i'.
Simplifying the positive part, we get √12 = 2√3, and including 'i', we have √(-12) = 2√3i.
If 2โ3i is the square root of -12, what is its square?
-12
To find the square, multiply 2√3i by itself:
(2√3i)² = (2√3)² × i²
= 12 × (-1)
= -12.
Express the square root of -12 in terms of the real and imaginary parts.
Real part: 0, Imaginary part: 2√3
The square root of -12 is completely imaginary, so the real part is 0 and the imaginary part is 2√3.
How does the square root of -12 relate to the square root of 12?
The square root of -12 is the square root of 12 multiplied by 'i'.
The square root of -12 can be expressed as √12 × √(-1)
= √12 × i
= 2√3i.
Is the square root of -12 a real number?
No, it is a complex number.
The square root of a negative number involves the imaginary unit 'i', which makes it a complex number, not a real number.

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.






