Square Root of -320
2026-02-28 01:21 Diff
https://brightchamps.com/en-us/math/algebra/square-root-of-minus-320

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Last updated on August 5, 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 concept of square roots extends into complex numbers when dealing with negative values. Here, we will discuss the square root of -320.

What is the Square Root of -320?

The square root is the inverse of the square of a number. Since -320 is negative, its square root is not a real number. Instead, we express it in terms of imaginary numbers. The square root of -320 can be expressed as √(-320) = √(320) × i, where i is the imaginary unit. In exponential form, it is expressed as (-320)^(1/2). √320 is approximately 17.8886, so √(-320) = 17.8886i, which is a complex number.

Finding the Square Root of -320

The square roots of negative numbers involve imaginary units. We use methods like prime factorization for positive components and then multiply by the imaginary unit. Let us now learn these methods:

  • Prime factorization method for positive components
  • Long division method for approximation Imaginary unit multiplication

Square Root of -320 by Prime Factorization Method

We find the prime factors of 320 first because -320 has the same factors multiplied by the imaginary unit.

Step 1: Finding the prime factors of 320 Breaking it down, we get 2 x 2 x 2 x 2 x 2 x 5: 2^5 x 5

Step 2: Now that we have the prime factors of 320, we pair them to simplify. The simplification gives us √320 = √(2^4 × 2 × 5) = 4√20 = 8√5.

Step 3: Since -320 is negative, multiply the result by i. Therefore, the square root of -320 is 8√5i.

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Square Root of -320 by Long Division Method

The long division method helps approximate the square root of positive numbers. For -320, we calculate the square root of 320 and then apply the imaginary unit.

Step 1: Group the digits of 320 from right to left. Here, it’s 32 and 0.

Step 2: Find the largest number whose square is less than or equal to 32. This number is 5 because 5 × 5 = 25.

Step 3: Subtract 25 from 32, giving a remainder of 7. Bring down the next digit, making the new dividend 70.

Step 4: Double the divisor, which is 10, and find a digit n such that (10n) × n is less than or equal to 70.

Step 5: Approximate further decimal places if needed. For √320, it approximates to 17.8886.

Step 6: Multiply by i for the negative square root: therefore, √(-320) = 17.8886i.

Square Root of -320 by Approximation Method

Approximation helps find the square root of a number swiftly. For -320, we calculate the square root of 320 and multiply by i.

Step 1: Determine the closest perfect squares around 320, which are 289 (17^2) and 324 (18^2). So, √320 is between 17 and 18.

Step 2: Use interpolation: (320 - 289) / (324 - 289) = 31 / 35 ≈ 0.886.

Step 3: Add this to the lower bound: 17 + 0.886 = 17.886.

Step 4: Multiply by i for the negative root: √(-320) = 17.886i.

Common Mistakes and How to Avoid Them in the Square Root of -320

Students often make mistakes when dealing with imaginary numbers, such as forgetting to include the imaginary unit i or incorrectly applying real number techniques. Let us examine some of these mistakes.

Problem 1

Can you help Max find the magnitude of a vector if its component is given as √(-45)?

Okay, lets begin

The magnitude of the vector is 6.708i.

Explanation

The magnitude involves the absolute value of the square root.

Here, √(-45) = √45 × i ≈ 6.708i.

Therefore, the magnitude is 6.708i.

Well explained 👍

Problem 2

A square-shaped field has an area of -320 square units. How would you describe the side length?

Okay, lets begin

The side length is 17.8886i units.

Explanation

For a negative area, we consider the imaginary side. √(-320) = 17.8886i.

Thus, the side length is 17.8886i units.

Well explained 👍

Problem 3

Calculate √(-320) × 5.

Okay, lets begin

The result is 89.443i.

Explanation

First, find √(-320) = 17.8886i.

Then, multiply by 5: 17.8886 × 5 = 89.443i.

Well explained 👍

Problem 4

What is the square root of (-100 + 20)?

Okay, lets begin

The square root is 8.9443i.

Explanation

First, calculate (-100 + 20) = -80.

Then, √(-80) = √80 × i = 8.9443i.

Well explained 👍

Problem 5

Find the perimeter of a rectangle with length 'l' as √(-128) units and width 'w' as 20 units.

Okay, lets begin

The perimeter is 40 + 22.6274i units.

Explanation

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

Perimeter = 2 × (√(-128) + 20) = 2 × (11.3137i + 20) = 40 + 22.6274i units.

Well explained 👍

FAQ on Square Root of -320

1.What is √(-320) in its simplest form?

The simplest form of √(-320) is 8√5i, derived from the prime factors of 320.

2.Can you express the square root of -320 in terms of real and imaginary components?

Yes, √(-320) = 0 + 17.8886i, where the real part is 0 and the imaginary part is 17.8886.

3.What is the square of -320?

The square of -320 is 102,400, as (-320) × (-320) = 102,400.

4.Is -320 a prime number?

No, -320 is not a prime number. It is negative and also composite when considering its positive counterpart.

5.What are the factors of 320?

The factors of 320 are 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 160, and 320.

Important Glossaries for the Square Root of -320

  • Square root: A square root is the inverse of a square. For negative numbers, it involves the imaginary unit i.
  • Complex number: A number that includes both real and imaginary parts, such as a + bi.
  • Imaginary unit (i): The imaginary unit i is defined as √(-1). It is used to express square roots of negative numbers.
  • Prime factorization: Breaking down a number into its prime factors.
  • Approximation: Estimating a value that is close to the actual value, often used for irrational numbers.

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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.

Fun Fact

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