Question

Resolva a questão da foto abaixo​

Answer 1

Resposta:

Teorema de Tales

$a)\\ \dfrac{4}{12}=\dfrac{x}{21}\\ \\ 12.x=4.21\\ \\ 12x=84\\ \\ x=84\div12\\ \\ \boxed{x=7}~\to letra~~c$

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$b)\\ \dfrac{9}{x}=\dfrac{18}{4}\\ \\ 18.x=4.9\\ \\ 18x=36\\ \\ x=36:18\\ \\\boxed{ x=2} \to letra~~b$