Question

Na figura,sendo a//b//c determine o valor de x




me ajudaaaa pfvvv véiiii






​

Answer 1

$\large\boxed{\begin{array}{l}\sf\dfrac{4\div4}{12\div4}=\dfrac{x}{21}\\\\\sf \dfrac{1}{3}=\dfrac{x}{21}\\\\\sf 3x=21\\\sf x=\dfrac{21}{3}\\\\\sf x=7\end{array}}$