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What is a Square Root?

Visual representation of square roots
Understanding square roots visually

A square root of a number is a value that, when multiplied by itself, gives the original number. It's like asking: "What number times itself equals this number?"

For example:

√9 = 3

Because 3 × 3 = 9

The symbol for square root is , called the "radical symbol". The number under the radical symbol is called the radicand.

Perfect squares like 1, 4, 9, 16, and 25 have whole number square roots. Numbers like 2, 3, 5, and 7 are not perfect squares, so their square roots are decimals that go on forever without repeating.

Square Root of 3

Visual representation of the square root of 3
Visualizing √3 using a right triangle

The square root of 3 is the number that when multiplied by itself equals 3. We write it as √3.

√3 ≈ 1.73205080757...
Key facts about √3:
  • It's an irrational number - its decimal goes on forever without repeating
  • It cannot be written as a simple fraction
  • It appears in geometry, especially in equilateral triangles
  • √3 is greater than 1.7 and less than 1.8
The square root of 3 is approximately 1.732. You can remember this because 1.732 × 1.732 = 2.999824, which is very close to 3!

Methods to Find √3

Step-by-step long division method for square root of 3
Long division method to calculate √3

Long Division Method

The long division method is the most accurate way to find square roots by hand. Here's how it works:

1
Write 3 as 3.000000 (add decimal places for accuracy)
2
Find the largest number whose square is ≤ 3 (1, since 1×1=1)
3
Subtract 1 from 3 to get 2, bring down two zeros to make 200
4
Double the result (1 becomes 2), and find digit (x) such that (20 + x) × x ≤ 200 (7, since 27×7=189)
5
Subtract 189 from 200 to get 11, bring down two zeros to make 1100
6
Continue the process to get more decimal places: √3 ≈ 1.732

Prime Factorization Method

This method works best for perfect squares. Since 3 is prime, we can write:

√3 = √3
But for composite numbers, we would pair identical factors.

Real-World Examples

Real-world applications of the square root of 3
Using √3 in geometry and engineering

The square root of 3 appears in many real-world situations:

Example 1: Equilateral Triangles
In an equilateral triangle with side length 2, the height is √3 because:

height = √(2² - 1²) = √(4 - 1) = √3
Example 2: Electrical Engineering
In three-phase power systems, the line-to-line voltage is √3 times the line-to-neutral voltage.

Example 3: Coordinate Geometry
The distance from (0,0) to (1, √3) is √(1² + (√3)²) = √(1 + 3) = √4 = 2

Example 4: Comparing Values
Which is larger: √3 or 1.7? Since 1.7 × 1.7 = 2.89 and 3 > 2.89, √3 > 1.7

Square Root Quiz

Test your understanding of square roots with this 5-question quiz. Choose the correct answer for each question.

1. What is the square root of 9?
2. Which of these is an irrational number?
3. Approximately what is √3?
4. What is the height of an equilateral triangle with side length 2?
5. Which method is best for finding √3?

Frequently Asked Questions

Here are answers to common questions about square roots:

Math Trivia

Discover interesting facts about square roots and mathematics:

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