Question

sendo A//b//c , determine x​

Answer 1

Utilizando o teorema de Tales, podemos achar as relações que seguem:

a)

$\frac{x}{4}~=~\frac{9}{12}\\\\\\Multiplicando~Cruzado\\\\\\12~.~x~=~4~.~9\\\\\\12x~=~36\\\\\\x~=~\frac{36}{12}\\\\\\\boxed{x~=~3}$

b)

$\frac{5}{x}~=~\frac{8}{x+12}\\\\\\Multiplicando~Cruzado\\\\\\5~.~(x+12)~=~8~.~x\\\\\\5x+60~=~8x\\\\\\8x-5x~=~60\\\\\\3x~=~60\\\\\\x~=~\frac{60}{3}\\\\\\\boxed{x~=~20}$