Answer:
2
Explanation:
A 45-90-45 triangle will have two equivalent side lengths and the hypotenuse. The hypotenuse is 4 and one of the side lengths is x. Since one of the side lengths is x, the other side length is x as well. Using the Pythagorean theorem, you can create this equation:
x^2 + x^2 = 4^2
or
2x^2 = 16
Now do the algebra:
2x^2 = 16
x^2 = 8
x = \sqrt{8\\}
which can be simplified as 2