Final answer:
The value of the cube's side length (c) is 4.5 yards.
Step-by-step explanation:
To find the value of the cube's side length (c), we can use the formula for the volume of a cube, which is V = c^3. Since the volume is given as 91.125 cubic yards, we can set up the equation 91.125 = c^3.
To solve for c, we can take the cube root of both sides of the equation, which gives us c = 4.5 yards.
Therefore, the value of the cube's side length is A) 4.5 yards.