The answer is actually b, 13(sqrt)2 inches
because you are cutting the diagonal of a square, the resulting triangle would be a 45, 45, 90 triangle, meaning that the ratio of each side is x, x, x(sqrt)2. since the length of the hypotenuse is 26 inches, that can be written as x(sqrt)2=26, and using algebra we can prove that x=(sqrt)338, which then by finding the value of each option, we find that 13(sqrt)2=(sqrt)338, meaning that x=13(sqrt)2.
