Respuesta :

sqdancefan

Answer:

  QS = 6

Step-by-step explanation:

Ratios of corresonding parts of similar triangles are equal.

  PQ/QS = JX/XZ

  9/QS = QS/4 . . . . . substituting given values

  36 = QS^2 . . . . . . . multiply by 4QS

  √36 = QS = 6 . . . . .take the square root