16.
8 inch diameter -> 4 inch radius -> 50.2 in^2 area of the pizza.
the ratio of cost to size of first pizza is 0.199 $ per square inch of pizza.
14 inch diameter -> 7 inch radius -> 153.9 in^2 area of the pizza.
the ratio of cost to size of first pizza is 0.103 $ per square inch of pizza.
Since the 14 inch diameter pizza has a lower cost (0.103 $) than the 8 inch diameter pizza (0.199 $), the 14 inch diameter pizza is the "better buy".
17.
the circumference will double, and the area will multiply by 4!
16. You want to buy the one with more pizza (meaning larger area) for its cost. The first pizza has area π(8/2)² = 16π and costs $10. (Notice I did 8/2 because 8 is the diameter and you want to square the radius.) The second pizza has area π(14/2)² = 49π and costs $16.
The better pizza has a higher "area-to-cost" ratio (high area, low cost). The first pizza has a ratio of 16π/10 = 5.027, and the second pizza has a ratio of 49π/16 = 9.621. The second pizza's ratio is higher, so it is the better buy.
17. I answered this in the other post
