EXPLANATION
We can represent the states in the following picture:
We can apply a Trigonometric ratio in order to get the value of the third side, assuming that it is called x:
[tex]\sin45=\frac{Opposite\text{ cathetus}}{Hypotenuse}=\frac{x}{8}[/tex]Multiplying both sides by 8:
[tex]8*\sin45=x[/tex]Switching sides:
[tex]x=8*\sin45[/tex]Multiplying terms:
[tex]x=4\sqrt{2}[/tex]In conclusion, the measure of the third side is approximately equivalent to 4√2 or 5.65