√992 at a glance
- Exact value
- 4√62
- Decimal (10 places)
- 31.4960314960
- Rounded
- 31.5 · 31.50 · 31.496
- Perfect square?
- No — between 31² and 32²
- Rational?
- Irrational
- Both square roots
- ±31.496031
- Prime factorization
- 2⁵ × 31
- Cube root
- 9.973262
How to simplify √992
Look for the largest perfect square that divides 992. Here it is 16 (4²), because 992 = 16 × 62 and 62 has no square factor left:
The prime factorization tells the same story: 992 = 2⁵ × 31. Each pair of equal primes leaves the radical as one factor, so 2² comes out and 2 × 31 stays inside.
992 has 2 square factors (4 and 16). Starting with a smaller one still works but takes more rounds: √992 = 2√248, and √248 can be simplified again. Using 16 straight away finishes in one step.
Check: (4√62)² = 4² × 62 = 16 × 62 = 992. As a decimal, 4√62 = 4 × 7.874007874 ≈ 31.4960314960.
Where √992 sits between perfect squares
961 = 31² and 1,024 = 32² are the nearest perfect squares, so √992 lies between 31 and 32. 992 is 31 above 961 and 32 below 1,024, so the root is closer to 31.
- Straight line between 961 and 1,024: 31.4921 (0.01% low)
- Tangent from 31, i.e. 31 + 31 ÷ 62: 31.5000 (0.01% high)
- Tangent from 32, i.e. 32 − 32 ÷ 64: 31.5000 (0.01% high)
For √992 the straight-line estimate is the closest of the three. The straight line always undershoots and the tangents always overshoot, because the square-root curve bends downward; near the middle of the gap the undershoot is smaller.
Finding √992 with the Babylonian method
Picture a rectangle with an area of 992 and one side x; the other side must be 992 ÷ x. Averaging the two sides gives a rectangle that is closer to a square, and the side of that square is exactly √992.
Start from the nearest whole number, 31 (31² = 961):
| Step | Guess x | 992 ÷ x | Average | Correct decimals |
|---|---|---|---|---|
| 1 | 31.0000000000 | 32.0000000000 | 31.5000000000 | 2 |
| 2 | 31.5000000000 | 31.4920634921 | 31.4960317460 | 6 |
| 3 | 31.4960317460 | 31.4960312461 | 31.4960314960 | 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 √992 = 31.4960314960 to every decimal shown.
√992 as a continued fraction
Every irrational square root has a continued fraction that repeats. For √992 the pattern is [31; 2, 62] with the block of 2 terms after the semicolon repeating forever. A pattern that never ends is one more proof that √992 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 |
|---|---|---|
| 31/1 | 31.0000000000 | 5.0 × 10⁻¹ |
| 63/2 | 31.5000000000 | 4.0 × 10⁻³ |
| 3,937/125 | 31.4960000000 | 3.1 × 10⁻⁵ |
| 7,937/252 | 31.4960317460 | 2.5 × 10⁻⁷ |
| 496,031/15,749 | 31.4960314941 | 2.0 × 10⁻⁹ |
| 999,999/31,750 | 31.4960314961 | < 10⁻¹⁰ |
The same fractions solve Pell’s equation, x² − 992y² = 1. Its smallest solution in positive whole numbers is x = 63, y = 2.
√992 in geometry and everyday measurements
- 992 square feet is 92.2 m². Laid out as a square — a small house footprint or a lot — it is about 31.5 ft (31 ft 6 in) on a side.
- 992 is not a sum of two whole-number squares — the prime factor 31 (one less than a multiple of 4) appears an odd number of times, which rules that out — so √992 is never the diagonal of a rectangle with whole-number sides. It is, however, the space diagonal of a 4 × 20 × 24 box, because 4² + 20² + 24² = 992.
- Since √992 = 4√62, a length of √992 is exactly 4 copies of the length √62 laid end to end.
Square roots near √992 and related roots
| Root | Simplest form | Decimal | Perfect square? |
|---|---|---|---|
| √989 | √989 | 31.4484 | No |
| √990 | 3√110 | 31.4643 | No |
| √991 | √991 | 31.4802 | No |
| √992 | 4√62 | 31.4960 | No |
| √993 | √993 | 31.5119 | No |
| √994 | √994 | 31.5278 | No |
| √995 | √995 | 31.5436 | No |
- The cube root of 992 is about 9.973262.
- Because 992 = 4 × 248, the root is twice √248: 2 × 15.748016 ≈ 31.496031.
Frequently asked questions
What is the square root of 992?
The square root of 992 is 4√62 in simplest radical form, which is about 31.4960314960. The negative root, −31.496031, also squares to 992.
Is the square root of 992 rational or irrational?
Irrational. 992 is not a perfect square — it falls between 961 and 1024 — and the square root of any whole number that is not a perfect square cannot be written as a fraction.
Can √992 be simplified?
Yes. The largest perfect square dividing 992 is 16, so √992 = √16 × √62 = 4√62.
What is √992 rounded to two decimal places?
√992 ≈ 31.50 to two decimal places (31.5 to one, 31.496 to three). Check: 31.50² = 992.25, close to 992.