Respuesta :

9514 1404 393

Answer:

  x = 10√3

Step-by-step explanation:

The Pythagorean theorem tells you ...

  FB^2 = BC^2 +CF^2

  FA^2 = FB^2 +BA^2

Substituting for FB^2, we have ...

  FA^2 = BC^2 +CF^2 +BA^2 = x^2 +x^2 +x^2

  FA^2 = 3x^2

  FA = x√3 = 30 . . . . take the square root and substitute for FA

  x = 30/√3

  x = 10√3