Respuesta :

9514 1404 393

Answer:

  B.  x = 2√11

Step-by-step explanation:

The square of the length of the diagonal is ...

  d² = 6² + 8² = 36 +64 = 100

Then the length of x is found from ...

  d² +x² = 12²

  x² = 144 -100 = 44 . . . . . subtract d²

  x = √44 . . . . . . take the square root

  x = 2√11