Help me with this pizza problem!?

You go to a pizza store and want to order a slice of pizza, but of course you want to get the best deal! The 2 pizzas are of equal quality.



You can order :

Option #1 a slice from a 12 - in pizza or

Option #2 a slice from a 14 - in pizza.

The 12 - in pizza is cut into 6 equal slices and the 14-in pizza is cut into 8 equal slices.

A slice from the 12 - in pizza costs $1.50 and a slice from the 14 - in pizza costs $1.70.

You must prove mathematically which option gets you the best deal? Then explain which option is the best deal %26amp; why鈥攅xplain in detail your reasoning.Help me with this pizza problem!?
Work it from area.

Area of any pizza = pi * r*r
r for 12 in pizza = 6 in
Area = 3.14 * 6^2 = 113 square inches.
Area of 6 slices = 113 square inches
Area of 1 slice = 113/6 = 18.84 square inches (seems like a lot).

Repeat the procedure for the 14 inch pizza. You should get 19.23 square inches. (There does not seem to be much difference. Check this carefully.)

Cost 12 inch pizza = 150 cents / 18.84 square inches = 7.96 cents per square inch.
Similarly the 14 inch pizza = 170 / 19.23 = 8.84 cents

The better deal is the 12 inch pizza

Comment
=======
This is an extremely valuable question. You would be surprised how many times it shows up. Over the years consumers have been trained to buy more because it usually means a reduction in the net cost. Lately that has not always been proven to be true.

My wife finds me to be a royal pain to shop with because I do this all the time. If I cannot figure out the question in my head (as I would not be able to in this question) it's her choice. But if I can then she has to wait for me to do it.

Edit
===
I hate to say this, but neither of the previous two answers seem to me to be correct. It is surprising the variety of answers that you will get. You have to take the deal that will give you the most quantity for your dollar. It is how much you get to eat that is important, not the cost per pizza nor the circumfrance which is only the outline. On second thought maybe the circumfrance one is OK. I'd have to work it out. Yes it does give the 12 inch pizza as the better deal. 23 cents per linear inch vs 30 cents per linear inch. (I'd still do it my way because it is actually more complete).
Work out the circumference of the two different sized pizzas first and then divide the circumference of each pizza by how many slices there are. then you will see how big each slice is, based on it's crust circumference. Compare the size of the crusts to the cost of the slice and one will be more expensive than the other.Help me with this pizza problem!?
I'm not sure if my method can be accepted. It's based on logic.



12-in pizza : $1.50 * 6 = $9

14-in pizza : $1.70 * 8 = $13.60



To see which option gets me the best deal, I calculate it base on the cost of each inch of both the pizzas.



12-in pizza : 9 / 12 = 0.75

14-in pizza : 13.60 / 14 = 0.97



Therefore, the 12-in pizza is definitely the best deal.

Hope this helps :)