Answer:
B
Explanation:
So we have a 45-45-90 triangle.
This is a special right triangle. In a 45-45-90 triangle, the side lengths are x, and the hypotenuse will be x√2
Since the hypotenuse is 3, we can set it equal to x√2 to solve for x. Therefore:

Divide both sides by √2:

Rationalize:

Our answer is B.