√185 at a glance
- Exact value
- √185
- Decimal (10 places)
- 13.6014705087
- Rounded
- 13.6 · 13.60 · 13.601
- Perfect square?
- No — between 13² and 14²
- Rational?
- Irrational
- Both square roots
- ±13.601471
- Prime factorization
- 5 × 37
- Cube root
- 5.698019
How to simplify √185
The prime factorization of 185 is 5 × 37. Every prime appears only once, so there is no pair to bring outside the radical — √185 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 185, 5 and 37 appear an odd number of times, so √185 is irrational and 13.6014705087 is a rounded value.
Where √185 sits between perfect squares
169 = 13² and 196 = 14² are the nearest perfect squares, so √185 lies between 13 and 14. 185 is 16 above 169 and 11 below 196, so the root is closer to 14.
- Straight line between 169 and 196: 13.5926 (0.07% low)
- Tangent from 13, i.e. 13 + 16 ÷ 26: 13.6154 (0.1% high)
- Tangent from 14, i.e. 14 − 11 ÷ 28: 13.6071 (0.04% high)
For √185 the tangent at 14 wins, missing by only 0.0057. Tangent estimates shine when the number sits close to a perfect square — here 185 is just 11 below 196.
Finding √185 with the Babylonian method
This is Newton’s method applied to f(x) = x² − 185: following the tangent line down to zero simplifies to averaging x with 185 ÷ x.
Start from the nearest whole number, 14 (14² = 196):
| Step | Guess x | 185 ÷ x | Average | Correct decimals |
|---|---|---|---|---|
| 1 | 14.0000000000 | 13.2142857143 | 13.6071428571 | 2 |
| 2 | 13.6071428571 | 13.5958005249 | 13.6014716910 | 5 |
| 3 | 13.6014716910 | 13.6014693264 | 13.6014705087 | all 10 shown |
The count of correct decimals went 2, 5 and all 10 over 3 steps — roughly doubling each time — until the guess matched √185 = 13.6014705087 to every decimal shown.
√185 as a continued fraction
Every irrational square root has a continued fraction that repeats. For √185 the pattern is [13; 1, 1, 1, 1, 26] with the block of 5 terms after the semicolon repeating forever. A pattern that never ends is one more proof that √185 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 | 6.0 × 10⁻¹ |
| 14/1 | 14.0000000000 | 4.0 × 10⁻¹ |
| 27/2 | 13.5000000000 | 1.0 × 10⁻¹ |
| 41/3 | 13.6666666667 | 6.5 × 10⁻² |
| 68/5 | 13.6000000000 | 1.5 × 10⁻³ |
| 1,809/133 | 13.6015037594 | 3.3 × 10⁻⁵ |
The same fractions solve Pell’s equation, x² − 185y² = 1. Its smallest solution in positive whole numbers is x = 9,249, y = 680. Because the period is odd, the equation with −1 on the right also has a solution: 68² − 185 × 5² = −1.
√185 in geometry and everyday measurements
- A square room or garden bed covering 185 square feet measures about 13.6 ft (13 ft 7 in) along each wall.
- 185 = 4² + 13² = 8² + 11², so by the Pythagorean theorem √185 is the diagonal of rectangles measuring 4 × 13 and 8 × 11 — and the distance between the points (0, 0) and (4, 13) on a grid.
Square roots near √185 and related roots
| Root | Simplest form | Decimal | Perfect square? |
|---|---|---|---|
| √182 | √182 | 13.4907 | No |
| √183 | √183 | 13.5277 | No |
| √184 | 2√46 | 13.5647 | No |
| √185 | √185 | 13.6015 | No |
| √186 | √186 | 13.6382 | No |
| √187 | √187 | 13.6748 | No |
| √188 | 2√47 | 13.7113 | No |
- The cube root of 185 is about 5.698019.
- Four times the radicand doubles the root: √740 = 2 × √185 ≈ 27.202941.
Frequently asked questions
What is the square root of 185?
The square root of 185 is √185, about 13.6014705087. The negative root, −13.601471, also squares to 185.
Is the square root of 185 rational or irrational?
Irrational. 185 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 √185 be simplified?
No. 185 = 5 × 37 has no repeated prime factor, so there is no perfect square to take out of the radical.
What is √185 rounded to two decimal places?
√185 ≈ 13.60 to two decimal places (13.6 to one, 13.601 to three). Check: 13.60² = 184.96, close to 185.