Question

Os números 5,7,10 e X formam, nessa ordem uma proporção. Determine o valor de x ?A) 20B)14C)8D)9.

Answer 1

$\large\boxed{\begin{array}{l}\rm\dfrac{5}{7}=\dfrac{10}{x}\\\\\rm 5x=70\\\rm x=\dfrac{70}{5}\\\\\rm x=14\\\huge\boxed{\boxed{\boxed{\boxed{\rm\dagger\red{\maltese}~\blue{alternativa~B}}}}}\end{array}}$