Answer:
 none of the choices is correct
Step-by-step explanation:
To find the length of the side of square 1, divide the perimeter, 104÷4 = 27 
That is the hypotenuse of the triangle.
The square of 27 is 729
Subtract the given square of Square 2, 576
729 - 576 = 153
Take the square root of 153 to find the length of the side of Square 3
√153= 12.37
I hope this helps. It's just a bit more challenging version of Pythagorean Theorem: a² + b² = c²