Rational and Irrational Number Operations Practice Test

Irrational, because any number containing a square root symbol is irrational.

Irrational, because $\sqrt{7}$ is irrational and $3$ is a nonzero rational; if $3\sqrt{7}$ were rational then $\sqrt{7}=\frac{3\sqrt{7}}{3}$ would be rational, a contradiction.

Rational, because $3$ is rational and multiplying by a rational always gives a rational result.

Rational, because $\sqrt{7}$ is close to $2.6$, and $3\times 2.6=7.8$ which is rational.