Square Root of 900

The square root of 900 is exactly 30, because 30 × 30 = 900. The negative number −30 squares to 900 too.

Whole numbers, decimals or fractions like 9/16. Negative numbers have no real root.
Decimal
30
Both real square roots
±30x² = 900 has two real solutions
Perfect power?
Yes
√90030

Show the work

  1. 900 is a perfect square: 302 = 900.
  2. So √900 = 30.

√900 at a glance

Exact value
30
Decimal (10 places)
30
Rounded
30
Perfect square?
Yes — 30²
Rational?
Rational (whole number)
Both square roots
±30
Prime factorization
2² × 3² × 5²
Cube root
9.654894

How to simplify √900

Write 900 as a product of primes and halve every exponent. Because each exponent is even, nothing is left under the radical sign:

900 = 2² × 3² × 5²
√900 = 2 × 3 × 5 = 30

900 has 14 factor pairs (1 × 900, 2 × 450, 3 × 300, 4 × 225, 5 × 180, 6 × 150, 9 × 100, 10 × 90, 12 × 75, 15 × 60, 18 × 50, 20 × 45, 25 × 36, 30 × 30). The pair with two equal numbers, 30 × 30, is what makes it a perfect square — and why it has an odd number of factors.

Every perfect square is also a sum of consecutive odd numbers starting at 1. Here 900 = 1 + 3 + 5 + 7 + … + 59, the first 30 odd numbers.

Where √900 sits between perfect squares

900 is 30². The perfect squares on either side are 841 (29²) and 961 (31²), so the gaps are 59 below and 61 above — consecutive squares always differ by consecutive odd numbers.

2929² = 8413030² = 9003131² = 961√900 = 30
√900 on a number line, with tenths marked between 29 and 31.

Finding √900 with the Babylonian method

Picture a rectangle with an area of 900 and one side x; the other side must be 900 ÷ x. Averaging the two sides gives a rectangle that is closer to a square, and the side of that square is exactly √900.

xnext = (x + 900 ÷ x) ÷ 2

To show the method at work on a perfect square, start one above the answer, at 31:

StepGuess x900 ÷ xAverageCorrect decimals
131.000000000029.032258064530.01612903231
230.016129032329.983879634630.00000433345
330.000004333429.999995666630.0000000000all 10 shown

The count of correct decimals went 1, 5 and all 10 over 3 steps — roughly doubling each time — until the guess matched √900 = 30.0000000000 to every decimal shown.

√900 in geometry and everyday measurements

  • 900 square feet is 83.6 m². Laid out as a square — a small house footprint or a lot — it is exactly 30 ft (30 ft) on a side.
  • 900 = 18² + 24², so 18, 24 and 30 form a Pythagorean triple: a right triangle with legs 18 and 24 has a hypotenuse of exactly 30.
RootSimplest formDecimalPerfect square?
√897√89729.9500No
√898√89829.9666No
√899√89929.9833No
√9003030.0000Yes
√901√90130.0167No
√902√90230.0333No
√903√90330.0500No
  • The cube root of 900 is about 9.654894.
  • Taking the square root twice gives the fourth root: √30 ≈ 5.477226.
  • Dividing by 100 divides the root by 10: √9 = √900 ÷ 10 ≈ 3.

Frequently asked questions

What is the square root of 900?

The square root of 900 is 30, because 30 × 30 = 900. Strictly, 900 has two square roots, 30 and −30; the √ symbol means the positive one.

Is the square root of 900 rational or irrational?

Rational. 900 is a perfect square, so its square root is the whole number 30.

Can √900 be simplified?

Yes, all the way to a whole number: √900 = 30.

What is √900 rounded to two decimal places?

√900 is exactly 30, or 30.00 written to two decimal places.

Need a different value? Use the Square root calculator, or browse the Square roots 1–1,000.