Verified Answer :

Leader

\(\sqrt{361}\) = 19
This is because 19 X 19 = 361.

So the square root of 361 is 19.

This is mostly the remembering of square of number.
you can remember the easy way by

\(20^2=400\)

which is greater than 361. 
Then you can reduce it to 19. And you will find out that

\(19^2=361\)

so the answer is 19

Cheers :)