Respuesta :

Answer:

Step-by-step explanation:

Given triangles are similar, so we setup a proportion  

(140-x)/81 = x/9

solving gives x = 14

AC = 140-x = 140-14 = 126

Answer:

The length of AC is 126 units.

Step-by-step explanation:

Given information: ED=9 units, AB=81 units, EC=x and AC=140-x.

In triangle ABC and EDC,

[tex]\angle A=\angle E[/tex]                           (Given)

[tex]\angle ACD=\angle ECD[/tex]                     (Given)

By AA property of similarity,

[tex]\triangle ABC\sim \angle EDC[/tex]

Both triangles ABC and EDC are similar. The corresponding sides of two similar triangles are proportional.

[tex]\frac{AB}{ED}=\frac{AC}{EC}[/tex]

[tex]\frac{81}{9}=\frac{140-x}{x}[/tex]

[tex]9=\frac{140-x}{x}[/tex]

[tex]9x=140-x[/tex]

[tex]9x+x=140[/tex]

[tex]10x=140[/tex]

Divide both sides by 10.

[tex]x=14[/tex]

The value of x is 14. So, the length of AC is

[tex]AC=140-14=126[/tex]

Therefore the length of AC is 126 units.