Find the square root of the numerator and simplify, if possible. For example, if you want to find the square root of 20/25, first find square root of 20. Because 20 = 4*5, 20^0.5 = (4^0.5)*(5^0.5). Therefore, 4^0.5 = 2, because 2*2 = 4. However, 5^0.5 cannot be simplified (there is no whole number that is the square root of 5) so write 2*5^0.5.
Take the square root of the denominator and simplify, if possible. In the example, 25^0.5 = 5, because 5*5 = 25.
Write a new fraction with the result from Step 1 as the numerator and the result from Step 2 as the denominator. In the example, 2*5^0.5/5.