Answer:
It is not correct.
Explanation:
From the picture we can see that the length of the sides of square C is 50 ft.
A right triangle is formed, where the diagonal of square C is the hypotenuse (c) and two sides of the square C are the other sides of the right triangle (a and b). From Pythagorean theorem:
c² = a² + b²
c² = 50² + 50²
c = √5000
c = 70.71 m