Why is the square root of a perfect square always rational?

  when we solve a square root it gives us a positive and a negative value given that it is the square root of a perfect square .

Explanation:

Lets take an example:

example: 25 if we take the square root of 25 it would be 5*5  

If a number is multiplied by itself then the product is said to be square of the number. And the number (i.e. 5) is called the square root

Perfect square number  

A number can be written as a product of two equal factors then the number is said to be a perfect square number