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Square Root of 75 Explained with Simplified Radical Form

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How to Find the Square Root of 75 Step by Step with Formula and Examples

The concept of square root of 75 is essential in mathematics and helps in solving real-world and exam-level problems efficiently. It is a commonly used topic for simplifying radical expressions and calculating approximate values.


Understanding Square Root of 75

A square root of 75 is a value which, when multiplied by itself, gives 75 as a result. In mathematical notation, this is written as √75. This concept is widely used in finding radical form, decimal values, and in simplification steps for surds in algebra and geometry.


Formula Used in Square Root of 75

The standard formula is: \( \sqrt{75} \)

To find the value, you can use prime factorization:
\( \sqrt{75} = \sqrt{3 \times 5 \times 5} = 5\sqrt{3} \)


How to Simplify Square Root of 75 (Step-by-Step)

Let’s break down the simplification of √75 to its simplest radical form:

1. Write the number as a product of its prime factors: 75 = 3 × 5 × 5.

2. Take out pairs of the same number (since √(a²) = a): The pair is two 5's.

3. Move one 5 outside the root: √75 = √(5×5×3) = 5√3.

4. Final simplified radical form: √75 = 5√3

So, the square root of 75 simplified is 5 times the square root of 3.


Square Root of 75 in Decimal Form

The decimal value of the square root of 75 (rounded to three decimal places) is:

√75 ≈ 8.660

This value is useful for calculator-based questions and quick approximations in exams.


Radical and Fractional Form of Square Root of 75

Radical form: √75
Simplest radical form: 5√3
Decimal form: 8.660
Fractional/approximate rational form: There is no exact rational fraction for √75, but you can approximate using fractions if required (e.g., 8⅔).


Comparison With Nearby Square Roots

See how √75 compares with close values:

Number Square Root Value Simplest Radical Form
20 4.472 2√5
75 8.660 5√3
76 8.718 irrational

This table shows how the square root of 75 fits between 20 and 76, helping you compare patterns in radical simplification.


Square Root of 75 by Long Division Method

To find √75 manually up to three decimals, use these steps:

1. Place a bar above the number in pairs starting from the decimal point to the left: 75.000000

2. Find the largest number whose square is less than or equal to 75 (8×8=64). Subtract 64 from 75 to get 11.

3. Bring down two zeros: new dividend is 1100.

4. Double the root so far (8×2=16); determine the largest digit X such that (160+X)×X ≤ 1100. X=6 (166×6=996). Subtract, continue.

5. Repeat the process for more decimal points (see detailed method above).

6. The answer is 8.660.

This long division method is used in exams for manual calculation of square roots.


Worked Example – Solving a Problem

Let’s solve a typical problem involving the square root of 75:

Problem: Simplify 20 + √75.

Step 1: Use the decimal value √75 ≈ 8.660.

Step 2: Add to 20: 20 + 8.660 = 28.660.

You can also use the simplified radical form, if required: 20 + 5√3.


Cube Root of 75

For completeness, the cube root of 75 is expressed as:

Cube root of 75 = ∛75 ≈ 4.217.

Cube roots are solved separately using their own procedures and help differentiate from square roots in advanced problems.
For more on cube roots, see Cube Root of Numbers.


Common Mistakes to Avoid

  • Confusing square root of 75 with a perfect square (it is NOT a perfect square, as 8²=64, 9²=81).
  • Forgetting to simplify √75 into 5√3 in radical questions.
  • Writing square root answers as fractions without rationalizing or approximating correctly.

Real-World Applications & Writing in Words

The square root of 75 appears in geometry (finding diagonal lengths), physics (measuring distances), and engineering calculations. In words, write as: “square root of seventy-five.”
An example: “Find the side of a square with area 75 square units.” The answer would be √75 units, simplified as 5√3 units.


Page Summary

We learned what the square root of 75 is, its simplified radical and decimal forms, how to calculate it step by step, and how it is used in real-world situations. For more maths concepts and practice, use Vedantu’s resources and internal links for in-depth learning.


Further Learning & Suggested Links

Explore related topics to master roots, surds, and mathematical simplification:


FAQs on Square Root of 75 Explained with Simplified Radical Form

1. What is the square root of 75 in simplest radical form?

The square root of 75 in simplest radical form is 5√3.

  • Factor 75 as 25 × 3.
  • Take the square root of 25, which is 5.
  • So, √75 = √(25 × 3) = 5√3.
This is the simplified radical form because 3 has no perfect square factors other than 1.

2. What is the decimal value of √75?

The decimal value of √75 is approximately 8.66.

  • Using a calculator: √75 ≈ 8.660254…
  • Rounded to two decimal places: 8.66.
This is useful when a numerical approximation is needed instead of radical form.

3. How do you simplify the square root of 75 step by step?

To simplify √75, factor out the largest perfect square and rewrite it as 5√3.

  • Step 1: Factor 75 = 25 × 3.
  • Step 2: √75 = √(25 × 3).
  • Step 3: √25 × √3 = 5√3.
This method uses the product rule of radicals: √(a × b) = √a × √b.

4. Is the square root of 75 a rational or irrational number?

The square root of 75 is an irrational number.

  • √75 = 5√3.
  • Since √3 is irrational, multiplying it by 5 still gives an irrational number.
  • Its decimal form (8.660254…) is non-terminating and non-repeating.
Therefore, √75 cannot be written as a simple fraction.

5. Can √75 be expressed as a whole number?

No, √75 cannot be expressed as a whole number because 75 is not a perfect square.

  • The closest perfect squares are 64 and 81.
  • √64 = 8 and √81 = 9.
  • Since 75 lies between 64 and 81, √75 lies between 8 and 9.
Therefore, √75 is not a whole number.

6. What are the factors of 75 used to simplify √75?

The factors of 75 used to simplify √75 are 25 and 3.

  • Prime factorization of 75 = 3 × 5 × 5.
  • Group the perfect square: 5 × 5 = 25.
  • So, √75 = √(25 × 3) = 5√3.
Using the largest perfect square factor makes simplification easier.

7. How do you find the square root of 75 using prime factorization?

Using prime factorization, √75 simplifies to 5√3.

  • Step 1: Prime factorize 75 = 3 × 5 × 5.
  • Step 2: Pair identical factors (5 × 5).
  • Step 3: Take one 5 outside the radical.
  • Step 4: Final answer = 5√3.
This method works for simplifying any non-perfect square.

8. Between which two integers does √75 lie?

The square root of 75 lies between 8 and 9.

  • 8² = 64
  • 9² = 81
  • Since 75 is between 64 and 81, √75 is between 8 and 9.
This helps estimate its approximate value without a calculator.

9. What is √75 rounded to the nearest tenth?

√75 rounded to the nearest tenth is 8.7.

  • Exact decimal: 8.660254…
  • Look at the hundredths digit (6).
  • Round the tenths digit (6) up to 7.
So, √75 ≈ 8.7 when rounded to one decimal place.

10. What is the difference between √75 and √49?

The difference between √75 and √49 is that √75 is irrational while √49 equals 7, a whole number.

  • √49 = 7 because 49 is a perfect square.
  • √75 = 5√3 ≈ 8.66.
  • 75 is not a perfect square, so its square root is irrational.
This highlights the difference between perfect squares and non-perfect squares.