√725 at a glance
- Exact value
- 5√29
- Decimal (10 places)
- 26.9258240357
- Rounded
- 26.9 · 26.93 · 26.926
- Perfect square?
- No — between 26² and 27²
- Rational?
- Irrational
- Both square roots
- ±26.925824
- Prime factorization
- 5² × 29
- Cube root
- 8.983509
How to simplify √725
Look for the largest perfect square that divides 725. Here it is 25 (5²), because 725 = 25 × 29 and 29 has no square factor left:
The prime factorization tells the same story: 725 = 5² × 29. Each pair of equal primes leaves the radical as one factor, so 5 comes out and 29 stays inside.
Check: (5√29)² = 5² × 29 = 25 × 29 = 725. As a decimal, 5√29 = 5 × 5.3851648071 ≈ 26.9258240357.
Where √725 sits between perfect squares
676 = 26² and 729 = 27² are the nearest perfect squares, so √725 lies between 26 and 27. 725 is 49 above 676 and 4 below 729, so the root is closer to 27.
- Straight line between 676 and 729: 26.9245 (0% low)
- Tangent from 26, i.e. 26 + 49 ÷ 52: 26.9423 (0.06% high)
- Tangent from 27, i.e. 27 − 4 ÷ 54: 26.9259 (0% high)
For √725 the tangent at 27 wins, missing by only 0.0001. Tangent estimates shine when the number sits close to a perfect square — here 725 is just 4 below 729.
Finding √725 with the Babylonian method
This is Newton’s method applied to f(x) = x² − 725: following the tangent line down to zero simplifies to averaging x with 725 ÷ x.
Start from the nearest whole number, 27 (27² = 729):
| Step | Guess x | 725 ÷ x | Average | Correct decimals |
|---|---|---|---|---|
| 1 | 27.0000000000 | 26.8518518519 | 26.9259259259 | 3 |
| 2 | 26.9259259259 | 26.9257221458 | 26.9258240359 | 9 |
| 3 | 26.9258240359 | 26.9258240355 | 26.9258240357 | all 10 shown |
The count of correct decimals went 3, 9 and all 10 over 3 steps — roughly doubling each time — until the guess matched √725 = 26.9258240357 to every decimal shown.
√725 as a continued fraction
Every irrational square root has a continued fraction that repeats. For √725 the pattern is [26; 1, 12, 2, 12, 1, 52] with the block of 6 terms after the semicolon repeating forever. A pattern that never ends is one more proof that √725 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 |
|---|---|---|
| 26/1 | 26.0000000000 | 9.3 × 10⁻¹ |
| 27/1 | 27.0000000000 | 7.4 × 10⁻² |
| 350/13 | 26.9230769231 | 2.7 × 10⁻³ |
| 727/27 | 26.9259259259 | 1.0 × 10⁻⁴ |
| 9,074/337 | 26.9258160237 | 8.0 × 10⁻⁶ |
| 9,801/364 | 26.9258241758 | 1.4 × 10⁻⁷ |
The same fractions solve Pell’s equation, x² − 725y² = 1. Its smallest solution in positive whole numbers is x = 9,801, y = 364.
√725 in geometry and everyday measurements
- 725 square feet is 67.4 m². Laid out as a square — a small house footprint or a lot — it is about 26.93 ft (26 ft 11 in) on a side.
- 725 = 7² + 26² = 10² + 25² = 14² + 23², so by the Pythagorean theorem √725 is the diagonal of rectangles measuring 7 × 26, 10 × 25 and 14 × 23 — and the distance between the points (0, 0) and (7, 26) on a grid.
- Since √725 = 5√29, a length of √725 is exactly 5 copies of the length √29 laid end to end.
Square roots near √725 and related roots
| Root | Simplest form | Decimal | Perfect square? |
|---|---|---|---|
| √722 | 19√2 | 26.8701 | No |
| √723 | √723 | 26.8887 | No |
| √724 | 2√181 | 26.9072 | No |
| √725 | 5√29 | 26.9258 | No |
| √726 | 11√6 | 26.9444 | No |
| √727 | √727 | 26.9629 | No |
| √728 | 2√182 | 26.9815 | No |
- The cube root of 725 is about 8.983509.
- Squaring undoes the root: (√725)² = 725, while 725² = 525,625 — the number whose square root is 725.
Frequently asked questions
What is the square root of 725?
The square root of 725 is 5√29 in simplest radical form, which is about 26.9258240357. The negative root, −26.925824, also squares to 725.
Is the square root of 725 rational or irrational?
Irrational. 725 is not a perfect square — it falls between 676 and 729 — and the square root of any whole number that is not a perfect square cannot be written as a fraction.
Can √725 be simplified?
Yes. The largest perfect square dividing 725 is 25, so √725 = √25 × √29 = 5√29.
What is √725 rounded to two decimal places?
√725 ≈ 26.93 to two decimal places (26.9 to one, 26.926 to three). Check: 26.93² = 725.2249, close to 725.