First, we recalled the formula we learned long ago for the area of a circle: π * r2 or "pi times the radius squared"
My friend took out his PDA, and we used 3.1416 for π. For our calculations, the value of π to ten-thousandths would be plenty, especially considering that pizza dimensions are imprecise enough to introduce a significant margin of error. This table shows how pizza diameter translates into area:
|Size (inches)||Area (square inches)|
We discovered that the 12" pizza we ordered had 34.6 more square inches of area than the 10" pizza. Since we ate 75% of the 12" pizza (84.8 square inches), the 10" pizza would not have been big enough, assuming we would notice the difference of six square inches. That's unlikely, but at least I got a second meal out of the leftovers!