Respuesta :

Answer:

8

Step-by-step explanation:

take a look at triangles SMN, and STR. Their side lengths are in the ratio of 1:2

you know this because if you look at side ST, it is made up of side SN and another side of the same length

so that means that 4:x = 1:2

x is equal to 8

The missing length is D.8