Is 6 sqaured a rational number

No it is not rational.

Step-by-step explanation:

By definition, that means there are two integers a and b with no common divisors where: a/b = square root of 6 ... Now this is the contradiction: if a is even and b is even, then they have a common divisor (2). Then our initial assumption must be false, so the square root of 6 cannot be rational.

Yes

Step-by-step explanation:

6 Squared is 36