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Simplest Radical Form of √72
6√2
≈ 8.485281
Coefficient (a) 6
Radicand (b) 2
Decimal value 8.485281

What this calculator does

This tool rewrites the square root of any non-negative whole number into its simplest radical form. A square root is in simplest form when no perfect-square factor (other than 1) remains under the radical sign. The result is expressed as a coefficient multiplied by a smaller square root, written as \(a\sqrt{b}\).

How to use it

Type any whole number into the input box and submit. The calculator returns three things: the coefficient \(a\) (the number pulled outside the radical), the radicand \(b\) (the number left inside the radical), and the decimal approximation of the root. If the number is a perfect square, the radicand becomes 1 and you simply get a whole number.

The formula explained

For an integer \(n\), we find the largest integer \(a\) such that \(a^2\) divides \(n\) evenly. We then set \(b = n / a^2\). Because we removed the biggest possible square factor, \(b\) is square-free, so \(a\sqrt{b}\) is the simplest radical form.

$$\sqrt{n} = a\sqrt{b}\qquad \text{where }a^{2}\text{ is the largest perfect-square factor of }n,\ b=\dfrac{n}{a^{2}}$$

This satisfies \(a^2 \cdot b = n\), which guarantees that \((a\sqrt{b})^2 = a^2 \cdot b = n\).

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Diagram showing a square root being split into a perfect square factor and a remaining factor
Simplifying \(\sqrt{n}\) by factoring out the largest perfect square to get \(a\sqrt{b}\).

Worked example

Simplify \(\sqrt{72}\). The largest square dividing 72 is 36 (since \(36 \times 2 = 72\)), so \(a = 6\) and \(b = 2\). Therefore

$$\sqrt{72} = 6\sqrt{2} \approx 8.485281$$

Check: \(6^2 \times 2 = 36 \times 2 = 72\). ✓

Worked example simplifying the square root of 72 into 6 times the square root of 2
Example: \(\sqrt{72} = \sqrt{36 \cdot 2} = 6\sqrt{2}\).

FAQ

What if the number is a perfect square? Then \(b = 1\) and the result is just the whole number \(a\). For example \(\sqrt{49} = 7\).

What if it cannot be simplified? If the number is already square-free (like 15), the coefficient stays 1 and the form remains \(\sqrt{15}\).

Does it work for 0? Yes — \(\sqrt{0} = 0\), with coefficient 0 and radicand 0.

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