Question

Square root of 256 is

• A. 18
• B. 16
• C. 14
• D. 24

Answer 1

The correct option is B 16

$256=2\times 2\times 2\times 2\times 2\times 2\times 2\times 2=2^2\times 2^2\times 2^2\times 2^2$
The square of a number contains every prime number twice.
So, the square root of 256 will contain $2\times 2\times 2\times 2=16$

Alternate: $256=2\times 2\times 2\times 2\times 2\times 2\times 2\times 2$

Make pairs of prime numbers

$256=2\times 2\times 2\times 2\times 2\times 2\times 2\times 2\downarrow \downarrow \downarrow \downarrow \sqrt{256}=2\times 2\times 2\times 2=16$