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Square Root of 20 Simplified Calculator

Reviewed by Calculator Editorial Team

The square root of 20 is a fundamental mathematical concept that appears in many real-world applications. This calculator provides a simplified way to find √20 and understand its significance.

What is the square root?

The square root of a number is a value that, when multiplied by itself, gives the original number. For a positive real number x, the square root is written as √x. By definition, √x is the non-negative number that, when squared, equals x.

Square Root Definition

For a non-negative real number x, the square root is defined as:

x = y such that y² = x and y ≥ 0

The square root function is the inverse of the squaring function. It's a continuous function that's defined for all non-negative real numbers and produces non-negative results.

How to calculate √20

Calculating the square root of 20 can be done using several methods, including:

  • Using a calculator (as shown in this page)
  • Estimation using perfect squares
  • Long division method
  • Newton's method for approximation

Square Root Formula

The square root of 20 can be expressed as:

√20 = √(4 × 5) = √4 × √5 = 2√5 ≈ 4.472135955

This simplified form shows that the square root of 20 is exactly twice the square root of 5. The decimal approximation is approximately 4.472.

Interpreting the result

The square root of 20 has several important interpretations:

  1. The length of the side of a square with area 20 square units
  2. The distance from the origin to a point (√20, 0) on the coordinate plane
  3. The standard deviation of a normal distribution with variance 20
  4. The magnitude of a vector with components (√20, 0)

Practical Interpretation

In practical terms, √20 ≈ 4.472 means that if you have a square with area 20 square units, each side would be approximately 4.472 units long.

Worked examples

Example 1: Finding the side length of a square

If a square has an area of 20 square meters, what is the length of each side?

Solution: The side length is the square root of the area, so √20 ≈ 4.472 meters.

Example 2: Distance calculation

If a point is located √20 units east of the origin on a coordinate plane, what is its x-coordinate?

Solution: The x-coordinate is √20 ≈ 4.472 units.

Example 3: Standard deviation

If a data set has a variance of 20, what is its standard deviation?

Solution: The standard deviation is the square root of the variance, so √20 ≈ 4.472.

FAQ

What is the exact value of √20?

The exact value of √20 is 2√5, which cannot be simplified further to a numerical value without using a decimal approximation.

How do I calculate √20 using a calculator?

You can use the calculator on this page or any scientific calculator by entering 20 and pressing the square root button.

What is the difference between √20 and -√20?

The square root function (√) always returns the non-negative root. The negative root is represented as -√20.

Can √20 be expressed as a fraction?

No, √20 cannot be expressed as a simple fraction because 20 is not a perfect square and its square root is irrational.