Respuesta :

9514 1404 393

Answer:

  √7

Step-by-step explanation:

The Pythagorean theorem tells you the square of the hypotenuse is equal to the sum of the squares of the sides. Let x represent the unknown side. Then we have ...

  x² +9² = (√88)²

  x² +81 = 88

  x² = 7 . . . subtract 81; next, take the (positive) square root

  x = √7 . . . . the third side