Could someone please help me find the missing X? Thank you :))) only if you know.

Answer:
x = 18[tex]\sqrt{2}[/tex]
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 + 9² = 27²
x² + 81 = 729 ( subtract 81 from both sides )
x² = 648 ( take the square root of both sides )
x = [tex]\sqrt{648}[/tex] = 18[tex]\sqrt{2}[/tex] ← exact value
x ≈ 25.5 ( to 1 dec. place )