Respuesta :

sqdancefan

Answer:

CD = 3

Step-by-step explanation:

Triangles CBA and CDE are similar (AA), so the side lengths are proportional.

(15-x)/20 = x/5

Multiplying by 20 gives ...

15 -x = 4x

15 = 5x . . . . . . add x

3 = x . . . . . . . . divide by 5

CD = x = 3