can some help me with the question below I don't know the answer

Answer:
y=4
Step-by-step explanation:
in a 45-45-90 triangle sides a and b are equal and the hypotenuse is [tex]a\sqrt{2}[/tex]
so in this case y is a leg, so it is 4
in case there is a part two where they ask what x is, it would be [tex]4\sqrt{2}[/tex]