Respuesta :

ameliaswan

Answer:

x = 15.6

Step-by-step explanation:

use the pythagorean theorem:

a² + b² = c²

a = 9

b = x

c = 18

(9)² + x² = (18)²

81 + x² = 324                    subtract 81 from both sides

x² = 243                            take the square root of both sides

x = √243

x = 15.6

good job