Answer:
C
Step-by-step explanation:
using Pythagoras' identity in the right triangle
the square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
x² + 4² = 9²
x² + 16 = 81 ( subtract 16 from both sides )
x² = 65 ( take square root of both sides )
x = [tex]\sqrt{65}[/tex]
