Respuesta :

Answer:

x = 9

Step-by-step explanation:

Similar Triangles

We are given a shape where two similar triangles are given. The similarity theorem states that the side lengths of the triangles must be proportional in the same scale factor.

The total length of the left side is 72+9 = 81 cm

The smaller length of the left side is 9 cm

The proportion is 81/9 = 9. This is the scale factor.

The total length of the right side is 3x - 20 + 56 = 3x + 36

The smaller length of the right side is 3x-20

The proportion must be equal to 9:

[tex]\displaystyle \frac{3x+36}{3x-20}=9[/tex]

Multiplying by 3x-20:

3x+36=9(3x-20)

Operating

3x+36=27x-180

Rearranging:

24x = 216

Dividing by 24:

x = 9