Question

4) Calcule *x* nós triângulos, sabendo que a AD é bissetriz relativa ao ângulo Â.​

Answer 1

Resposta:

a) 14

b) 20

c) 20

Explicação passo a passo:

a) 12 = x                    

  3     21

   x = 14

b) 15 = 12

   25    x

   x = 20

c) 35 = 42

   3x    4x - 8

   x = 20

Answer 2

$\boxed{\begin{array}{l}\tt a)~\sf\dfrac{18}{21}=\dfrac{12}{x}\\\sf 18x=21\cdot12\\\sf x=\dfrac{21\cdot12}{18}\\\sf x=\dfrac{\diagup\!\!\!\!3\cdot7\cdot2\cdot\diagup\!\!\!\!6}{\diagup\!\!\!\!3\cdot\diagup\!\!\!\!\!6}\\\\\sf x=14\end{array}}$

$\boxed{\begin{array}{l}\tt b)~\sf\dfrac{25}{x}=\dfrac{15}{12}\\\sf 15x=12\cdot25\\\sf x=\dfrac{\diagup\!\!\!\!3\cdot4\cdot\diagup\!\!\!\!5\cdot5}{\diagup\!\!\!\!\!3\cdot\diagup\!\!\!\!\!5}\\\\\sf x=4\cdot5\\\sf x=20\end{array}}$

$\boxed{\begin{array}{l}\tt c)~\sf\dfrac{4x-8}{3x}=\dfrac{42\div7}{35\div7}\\\\\sf\dfrac{4x-8}{3x}=\dfrac{6}{5}\\\\\sf 5\cdot(4x-8)=6\cdot3x\\\sf 20x-40=18x\\\sf 20x-18x=40\\\sf 2x=40\\\sf x=\dfrac{40}{2}\\\\\sf x=20\end{array}}$