The area of a circle is a=×π. Now just plug in the values you have which is you area. 201=×π now divide by pi on both sides you that you get about 64=. Now find the square root on both sides which will then give you 8 as your radius. To find diameter from radius you have to multiply by 2. 8*2=16
The reason is because the is 16 ounces in a pound so you would do 8.99/16 and you get .56 per ounce but is you do 6.50/12 you get .54 per ounce which is a better deal.