Advice:
I've seen this around quite a bit. what image is it referring to? I cannot answer this because there is no image.
I believe the answer to your question is b.
Our hint here is the identity of the shape. It is mentioned that the shape is a square. By definition, a square is a two-dimensional with four sides having equal measures. The formula for its area is:
A = s², where s is the length of its side
Substituting the value of A,
25/36 in² = s²
s = √(25/36)
s = 5/6 inches or 0.833 inches