Yes, they are.
If the value applied in the radical is not a perfect square, it is irrational. 25; 400; and 625 are perfect squares and are rational when applied in a radical.
20 squared is 400 which is a rational number
Square root 400 - square root 196 = 6
it is 400
Yes, they are.
The square roots of some numbers are rational: eg sqrt(4) = 2, sqrt(0.04) = 0.2, sqrt(400) = 20 The square roots of some numbers are irrational eg sqrt(2) = 1.414 (approx), sqrt(0.02) = 0.1414 (approx), sqrt(200) = 14.14 (approx) The square roots of negative numbers are neither rational nor irrational, but imaginary.
If the value applied in the radical is not a perfect square, it is irrational. 25; 400; and 625 are perfect squares and are rational when applied in a radical.
20 squared is 400 which is a rational number
20 squared is 400 which is a rational number
Square root 400 - square root 196 = 6
No because 400 is a rational number that can be expressed as a fraction in the form of 400/1
2020^2 = 400400 is a perfect square.......perfect square  noun Mathematics .1.a rational number that is equal to the square of another rational number.2.a polynomial that is the square of another polynomial.Origin:1935-40
Square root of 400 simplified is 20.
The square root of 400 is 20.
Neither because the square root of 400 is 20
20 and -20