What is Square Root of 81

• Square root of 81 is written as $\sqrt{81}$ (Radical form).
• Square root of 81 = $\sqrt{81}$ = $\sqrt{9 \times 9}$ = 9
• In the exponential form, the square root of 81 is expressed as $(81)^\frac{1}{2}$.

We will now calculate the square root of 81 by Prime Factorisation.

Square Root of 81 By Prime Factorization Method

• Step 1: Prime factors of 81: 3 x 3 x 3 x 3
• Step 2: Prime factors of 81 in pairs: (3 x 3) x (3 x 3)
• Step 3: Now square root of 81:

$\sqrt{81} = \sqrt{(3 \times 3) \times (3 \times 3)}$

$\sqrt{81} = \sqrt{ 3^2 \times3^2}$

$\sqrt{81} = 9$

Therefore, the square root of 81 is ±9