1. The circumference of the circle in terms of \( \pi \) is \( \boxed{8\pi \) yards.
2. To find the radius of the circle when the circumference is given, we use the formula \( C = 2\pi r \), where \( C \) is the circumference and \( r \) is the radius. Given \( C = 77.872 \) millimeters, we can rearrange the formula to solve for \( r \):
\[ r = \frac{C}{2\pi} = \frac{77.872}{2 \times 3.14} \approx \frac{77.872}{6.28} \approx 12.4 \text{ mm} \]
So, the radius of the circle is \( \boxed{12.4 \) mm.
3. To find the length of the crust around the larger pizza, we first need to find the radius of the larger pizza. Since 1 inch is equal to 2.54 centimeters, the radius of the larger pizza is \( \frac{31.75}{2} = 15.875 \) centimeters. Now, we use the formula \( C = 2\pi r \) to find the circumference of the larger pizza:
\[ C = 2 \times 3.14 \times 15.875 \approx 99.70 \] inches.
So, the length of the crust around the larger pizza is \( \boxed{99.70 \) inches.
