√160 at a glance
- Exact value
- 4√10
- Decimal (10 places)
- 12.6491106407
- Rounded
- 12.6 · 12.65 · 12.649
- Perfect square?
- No — between 12² and 13²
- Rational?
- Irrational
- Both square roots
- ±12.649111
- Prime factorization
- 2⁵ × 5
- Cube root
- 5.428835
How to simplify √160
Look for the largest perfect square that divides 160. Here it is 16 (4²), because 160 = 16 × 10 and 10 has no square factor left:
The prime factorization tells the same story: 160 = 2⁵ × 5. Each pair of equal primes leaves the radical as one factor, so 2² comes out and 2 × 5 stays inside.
160 has 2 square factors (4 and 16). Starting with a smaller one still works but takes more rounds: √160 = 2√40, and √40 can be simplified again. Using 16 straight away finishes in one step.
Check: (4√10)² = 4² × 10 = 16 × 10 = 160. As a decimal, 4√10 = 4 × 3.1622776602 ≈ 12.6491106407.
Where √160 sits between perfect squares
144 = 12² and 169 = 13² are the nearest perfect squares, so √160 lies between 12 and 13. 160 is 16 above 144 and 9 below 169, so the root is closer to 13.
- Straight line between 144 and 169: 12.6400 (0.07% low)
- Tangent from 12, i.e. 12 + 16 ÷ 24: 12.6667 (0.14% high)
- Tangent from 13, i.e. 13 − 9 ÷ 26: 12.6538 (0.04% high)
For √160 the tangent at 13 wins, missing by only 0.0047. Tangent estimates shine when the number sits close to a perfect square — here 160 is just 9 below 169.
Finding √160 with the Babylonian method
Picture a rectangle with an area of 160 and one side x; the other side must be 160 ÷ x. Averaging the two sides gives a rectangle that is closer to a square, and the side of that square is exactly √160.
Start from the nearest whole number, 13 (13² = 169):
| Step | Guess x | 160 ÷ x | Average | Correct decimals |
|---|---|---|---|---|
| 1 | 13.0000000000 | 12.3076923077 | 12.6538461538 | 2 |
| 2 | 12.6538461538 | 12.6443768997 | 12.6491115268 | 6 |
| 3 | 12.6491115268 | 12.6491097546 | 12.6491106407 | all 10 shown |
The count of correct decimals went 2, 6 and all 10 over 3 steps — roughly doubling each time — until the guess matched √160 = 12.6491106407 to every decimal shown.
√160 as a continued fraction
Every irrational square root has a continued fraction that repeats. For √160 the pattern is [12; 1, 1, 1, 5, 1, 1, 1, 24] with the block of 8 terms after the semicolon repeating forever. A pattern that never ends is one more proof that √160 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 |
|---|---|---|
| 12/1 | 12.0000000000 | 6.5 × 10⁻¹ |
| 13/1 | 13.0000000000 | 3.5 × 10⁻¹ |
| 25/2 | 12.5000000000 | 1.5 × 10⁻¹ |
| 38/3 | 12.6666666667 | 1.8 × 10⁻² |
| 215/17 | 12.6470588235 | 2.1 × 10⁻³ |
| 253/20 | 12.6500000000 | 8.9 × 10⁻⁴ |
The same fractions solve Pell’s equation, x² − 160y² = 1. Its smallest solution in positive whole numbers is x = 721, y = 57.
√160 in geometry and everyday measurements
- A square room or garden bed covering 160 square feet measures about 12.65 ft (12 ft 8 in) along each wall.
- 160 = 4² + 12², so by the Pythagorean theorem √160 is the diagonal of a 4 × 12 rectangle — and the distance between the points (0, 0) and (4, 12) on a grid.
- Since √160 = 4√10, a length of √160 is exactly 4 copies of the length √10 laid end to end.
Square roots near √160 and related roots
| Root | Simplest form | Decimal | Perfect square? |
|---|---|---|---|
| √157 | √157 | 12.5300 | No |
| √158 | √158 | 12.5698 | No |
| √159 | √159 | 12.6095 | No |
| √160 | 4√10 | 12.6491 | No |
| √161 | √161 | 12.6886 | No |
| √162 | 9√2 | 12.7279 | No |
| √163 | √163 | 12.7671 | No |
- The cube root of 160 is about 5.428835.
- Four times the radicand doubles the root: √640 = 2 × √160 ≈ 25.298221.
Frequently asked questions
What is the square root of 160?
The square root of 160 is 4√10 in simplest radical form, which is about 12.6491106407. The negative root, −12.649111, also squares to 160.
Is the square root of 160 rational or irrational?
Irrational. 160 is not a perfect square — it falls between 144 and 169 — and the square root of any whole number that is not a perfect square cannot be written as a fraction.
Can √160 be simplified?
Yes. The largest perfect square dividing 160 is 16, so √160 = √16 × √10 = 4√10.
What is √160 rounded to two decimal places?
√160 ≈ 12.65 to two decimal places (12.6 to one, 12.649 to three). Check: 12.65² = 160.0225, close to 160.