Question

Assinale a alternativa que mostra apenas números racionais: * 3 pontos 3/1; 4/2; 5; 0,5; √19; 8/2; √4; 8; 0,3; 0,56; √19; 3; 9/2; 3,5; 1/2; 2; 0,45; 10/2; 4; √2

Answer 1

Resposta:

A alternativa correta é a letra b.

Explicação passo-a-passo:

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Os números racionais são aqueles que podem ser representados sob a forma de uma fração. Logo,

$a) \quad \rightarrow \quad \mathbf{Falsa}\\\\\dfrac{3}{1}=3 \quad \rightarrow \quad \mathbi{racional}\\\\\\\dfrac{4}{2}=2 \quad \rightarrow \quad \mathbi{racional}\\\\\\5=\dfrac{10}{2} \quad \rightarrow \quad \mathbi{racional}\\\\\\0{,}5=\dfrac{1}{2} \quad \rightarrow \quad \mathbi{racional}\\\\\\\sqrt{19} \quad \rightarrow \quad \mathbi{irracional}$

$b) \quad \rightarrow \quad \mathbf{Verdadeira}\\\\\dfrac{8}{2}=4 \quad \rightarrow \quad \mathbi{racional}\\\\\\\sqrt{4}=2=\dfrac{4}{2} \quad \rightarrow \quad \mathbi{racional}\\\\\\8=\dfrac{16}{2} \quad \rightarrow \quad \mathbi{racional}\\\\\\0{,}3=\dfrac{3}{10} \quad \rightarrow \quad \mathbi{racional}\\\\\\0{,}56=\dfrac{56}{100} \quad \rightarrow \quad \mathbi{racional}$

$c) \quad \rightarrow \quad \mathbf{Falsa}\\\\\\\sqrt{19} \quad \rightarrow \quad \mathbi{irracional}\\\\\\3=\dfrac{9}{3} \quad \rightarrow \quad \mathbi{racional}\\\\\\\dfrac{9}{2}=4{,}5 \quad \rightarrow \quad \mathbi{racional}\\\\\\3{,}5=\dfrac{7}{2} \quad \rightarrow \quad \mathbi{racional}\\\\\\\dfrac{1}{2}=0{,}5 \quad \rightarrow \quad \mathbi{racional}$

$d) \quad \rightarrow \quad \mathbf{Falsa}\\\\2=\dfrac{4}{2} \quad \rightarrow \quad \mathbi{racional}\\\\\\0{,}45=\dfrac{45}{100} \quad \rightarrow \quad \mathbi{racional}\\\\\\\dfrac{10}{2}=5 \quad \rightarrow \quad \mathbi{racional}\\\\\\4=\dfrac{8}{2} \quad \rightarrow \quad \mathbi{racional}\\\\\\\sqrt{2} \quad \rightarrow \quad \mathbi{irracional}$