Qual alternativa apresenta uma fração com denominador sendo um número irracional? Escolha 1 resposta: A (1)/(sqrt (9)) B (1)/(sqrt (3)) C (1)/(sqrt (25)) D (1)/(sqrt (4))

The question asks for a fraction where the denominator is an irrational number. An irrational number is a number that cannot be expressed as a ratio of two integers. In other words, it cannot be written as a simple fraction. <br /><br />Option A: $\frac {1}{\sqrt {9}}$ simplifies to $\frac {1}{3}$, which is a rational number.<br />Option B: $\frac {1}{\sqrt {3}}$ cannot be simplified to a rational number, so it is an irrational number.<br />Option C: $\frac {1}{\sqrt {25}}$ simplifies to $\frac {1}{5}$, which is a rational number.<br />Option D: $\frac {1}{\sqrt {4}}$ simplifies to $\frac {1}{2}$, which is a rational number.<br /><br />Therefore, the correct answer is option B.