Answer:
[tex]4\sqrt{3}[/tex]
Step-by-step explanation:
By the Pythagorean theorem,
[tex]4^2+x^2=8^2\\16+x^2=64\\x^2=64-16=48\\x=\sqrt{48}=\sqrt{16\times 3} = \sqrt{4^2\times 3}=4\sqrt{3}[/tex]
