To find the best cost per square inch, we must first find the area of each pizza.
Using the formula for the area of a circle, r2π:
Medium pizza: 62π = 36π = 113.04 in2.
Large pizza: 92π = 81π = 254.34 in2.
Remember, 12 in. and 18 in. are the diameters of the pizzas.
Now with the area, we can determine the price per square inch of pizza. We can convert to cents for a better indicator of price.
Medium pizza: $10 = 1000 cents
Large pizza: $16 = 1600 cents