Answer:
x=6
Explanation:
In a square, its angles are all 90 degrees. So, cutting a square in half into two triangles from corner to corner produces 45 degree angles on both sides. Since the triangles are now 45-45-90 triangles, we can use the rule where the hypotenuse of the triangle is equal to the square root of 2 times the length of either side. So, the side length is 6.