The perimeter of a circle, also known as the circumference, can be calculated using the formula:
\[ C = \pi \times d \]
where \( C \) is the circumference and \( d \) is the diameter of the circle.
Given that the diameter of the circle is 25 yards, we can substitute this value into the formula:
\[ C = \pi \times 25 \]
Using the approximate value of \( \pi \) (about 3.14):
\[ C \approx 3.14 \times 25 \approx 78.5 \text{ yards} \]
Therefore, the perimeter (circumference) of the circle is approximately 78.5 yards.