#### Answer

$\sqrt9$, which is equal to 3, is
a natural number,
a whole number,
an integer,
a rational number, and
a real number.

#### Work Step by Step

RECALL:
(i) Natural (or Counting) Numbers are $1, 2, 3, ...$
(ii) Whole Numbers are $0, 1, 2, 3, ...$
(ii) Integers are $..., -3, -2, -1, 0, 1, 2, 3, ...$
(iv) Rational Numbers are numbers that can be expressed as a quotient of two integers.
(v) Irrational Numbers are numbers that cannot be expressed as a quotient of two integers.
(vi) Real Numbers are the set of all rational and irrational numbers.
$\sqrt9=\sqrt{3^2} = 3$.
Thus, the number $\sqrt{9}$, which is equal to 3, is
a natural number,
a whole number,
an integer,
a rational number, and
a real number.