The area of a circle is found by pi*r^2
We can plug in the values we know to solve for the radius.
12.56 = 3.14*r^2
Divide both sides by pi.
12.56/3.14 = r^2
Square root both sides.
r = 2 yards
The diameter of a circle is twice as long as the radius, so the answer is 4 yards.