The square root of 40 is a rational number if 40 is a perfect square. It is an irrational number if it is not a perfect square. Since 40 is not a perfect square, it is an irrational number. This means that the answer to "the square root of 40?" will have an infinite number of decimals. The decimals will not terminate and you cannot make it into an exact fraction.
√40 is an irrational number
