√195 at a glance
- Exact value
- √195
- Decimal (10 places)
- 13.9642400438
- Rounded
- 14.0 · 13.96 · 13.964
- Perfect square?
- No — between 13² and 14²
- Rational?
- Irrational
- Both square roots
- ±13.964240
- Prime factorization
- 3 × 5 × 13
- Cube root
- 5.798890
How to simplify √195
The prime factorization of 195 is 3 × 5 × 13. Every prime appears only once, so there is no pair to bring outside the radical — √195 is already in simplest form (a "square-free" radicand).
A whole number has a rational square root only when every prime in its factorization appears an even number of times. In 195, 3, 5 and 13 appear an odd number of times, so √195 is irrational and 13.9642400438 is a rounded value.
Where √195 sits between perfect squares
169 = 13² and 196 = 14² are the nearest perfect squares, so √195 lies between 13 and 14. 195 is 26 above 169 and 1 below 196, so the root is closer to 14.
- Straight line between 169 and 196: 13.9630 (0.01% low)
- Tangent from 13, i.e. 13 + 26 ÷ 26: 14.0000 (0.26% high)
- Tangent from 14, i.e. 14 − 1 ÷ 28: 13.9643 (0% high)
For √195 the tangent at 14 wins, missing by only 0. Tangent estimates shine when the number sits close to a perfect square — here 195 is just 1 below 196.
Finding √195 with the Babylonian method
If a guess is too big, 195 ÷ x is too small by about the same amount, so their average lands much closer. In fact an error of e shrinks to roughly e² ÷ (2√195) in one step.
Start from the nearest whole number, 14 (14² = 196):
| Step | Guess x | 195 ÷ x | Average | Correct decimals |
|---|---|---|---|---|
| 1 | 14.0000000000 | 13.9285714286 | 13.9642857143 | 4 |
| 2 | 13.9642857143 | 13.9641943734 | 13.9642400438 | 10 |
| 3 | 13.9642400438 | 13.9642400437 | 13.9642400438 | all 10 shown |
The count of correct decimals went 4, 10 and all 10 over 3 steps — roughly doubling each time — until the guess matched √195 = 13.9642400438 to every decimal shown.
√195 as a continued fraction
Every irrational square root has a continued fraction that repeats. For √195 the pattern is [13; 1, 26] with the block of 2 terms after the semicolon repeating forever. A pattern that never ends is one more proof that √195 is irrational.
Cutting the continued fraction off early gives the best fractions for approximating the root — no fraction with a smaller denominator comes closer:
| Fraction | Decimal | Error |
|---|---|---|
| 13/1 | 13.0000000000 | 9.6 × 10⁻¹ |
| 14/1 | 14.0000000000 | 3.6 × 10⁻² |
| 377/27 | 13.9629629630 | 1.3 × 10⁻³ |
| 391/28 | 13.9642857143 | 4.6 × 10⁻⁵ |
| 10,543/755 | 13.9642384106 | 1.6 × 10⁻⁶ |
| 10,934/783 | 13.9642401022 | 5.8 × 10⁻⁸ |
The same fractions solve Pell’s equation, x² − 195y² = 1. Its smallest solution in positive whole numbers is x = 14, y = 1.
√195 in geometry and everyday measurements
- A square room or garden bed covering 195 square feet measures about 13.96 ft (14 ft) along each wall.
- 195 is not a sum of two whole-number squares — the prime factor 3 (one less than a multiple of 4) appears an odd number of times, which rules that out — so √195 is never the diagonal of a rectangle with whole-number sides. It is, however, the space diagonal of a 1 × 5 × 13 box, because 1² + 5² + 13² = 195.
Square roots near √195 and related roots
| Root | Simplest form | Decimal | Perfect square? |
|---|---|---|---|
| √192 | 8√3 | 13.8564 | No |
| √193 | √193 | 13.8924 | No |
| √194 | √194 | 13.9284 | No |
| √195 | √195 | 13.9642 | No |
| √196 | 14 | 14.0000 | Yes |
| √197 | √197 | 14.0357 | No |
| √198 | 3√22 | 14.0712 | No |
- The cube root of 195 is about 5.798890.
- Four times the radicand doubles the root: √780 = 2 × √195 ≈ 27.92848.
Frequently asked questions
What is the square root of 195?
The square root of 195 is √195, about 13.9642400438. The negative root, −13.964240, also squares to 195.
Is the square root of 195 rational or irrational?
Irrational. 195 is not a perfect square — it falls between 169 and 196 — and the square root of any whole number that is not a perfect square cannot be written as a fraction.
Can √195 be simplified?
No. 195 = 3 × 5 × 13 has no repeated prime factor, so there is no perfect square to take out of the radical.
What is √195 rounded to two decimal places?
√195 ≈ 13.96 to two decimal places (14.0 to one, 13.964 to three). Check: 13.96² = 194.8816, close to 195.