It depends how big you want your slices to be. say one slice is a 3 by 4 rectangle. you would get about 4 slices, plus 2 smaller slices. Or, you could make them half the size and get about 10. It all depends how big they're going to be.
A reasonable number would be eight. Anything more than than would, perhaps, be too small a serving.
12
The slices can range 9 to 24. Most sicilian pizzas are cut into 16 squares. However, it can differ based on the size of the pie.
It all depends how big you want to slice the pieces :). I would say 8 slices is a nice amount. If everyone is very hungry it will probably be 4 slices.
It will depend on the size of the portions you wish to serve but around 12 slices.
54 ÷ 6 = 9 slices on each plate.
This would depend on the size of the pie. A normal 9-inch pie will generally provide six servings, unless everybody is on a diet, in which case eight servings. So 25 people divided by 6 servings would be five pies, with five slices left over. Or, you could cut thinner slices and get by with four pies. A smaller pie of about 6 inches in diameter will provide four servings, so you'd need seven pies.
As many as you want. You decide.
18
18
Don't know about a 9 inch but there are 1.5 quarts in a 9.5 inch pie plate.
If you mean 3*pi then it is greater than 9
r2*pie=circumference 9(9)*pie 81*pie 254
6 Slices = 2-3 pax