Answer:
 50.24 square yards does the dog have access to.
Explanation:
Area of a circle(A) is given by:
 .....[1]
where
r is radius of the circle
As per the statement:
Wyatt's dog is tethered to a post in his yard. if the rope tied to the dog is 12 feet long
⇒radius(r) = 12 feet long 
use 3.14 for π
Substitute these in [1] we get;

⇒

Use conversion:
1 square feet = 
 sqaure yard
then;
452.16 square feet = 
 = 50.24 square yards.
Therefore, 50.24 square yards does the dog have access to.